Cold sores are common, annoying and, for a lot of people, a familiar visitor. They're caused by herpes simplex virus type 1 (HSV-1), which around 64% of people under 50 carry worldwide.1 Knowing the cold sore stages helps you spot one early, treat it at the right moment and avoid passing it on.
Most cold sores follow the same pattern, from the first tingle to fully healed skin, and usually clear up within 10 days.2 Below, we walk through each stage, how contagious you are along the way and which treatments help most, and when.
The tingle is your best window. Treating a cold sore at the very first sign gives you the best shot at a shorter, milder outbreak.
What causes cold sores?
Cold sores are small blisters that usually appear on or around your lips. They can also pop up on your nose, chin or cheeks.
Most people pick up HSV-1 as a child, through close contact with someone who has a cold sore.2 After that, the virus doesn't leave. It settles in your nerve cells and stays inactive most of the time.1
Every so often, something wakes it up. Common cold sore triggers include illness, stress, tiredness, strong sunlight and periods.2
Carrying the cold sore virus is really common, so there's nothing unusual about getting one. Learning your own triggers helps you plan ahead.
There's no cure for HSV-1. But cold sores are very treatable, and there's plenty you can do to make each one easier.
What are the 5 cold sore stages?
The stages of a cold sore are roughly the same for everyone, though timings vary from person to person. Here's what a typical repeat cold sore looks like, day by day.
“The first tingle is the best time to start antiviral cold sore treatment. You can pass the virus on from that early warning until the sore has completely healed, so avoid kissing and oral sex throughout that time. Never kiss a baby while you have a cold sore.
Ana Carolina GoncalvesSuperintendent Pharmacist
Stage 1: tingling (days 1 to 2)
It starts before you can see anything. You'll usually feel tingling, itching or burning on the spot where the sore is about to appear.2
This is the stage that matters most for treatment. Antiviral medicines work best when they're started as early as possible, ideally at the first tingle.3 And yes, you're already contagious at this point.2
Get cold sores often? Keeping treatment at home means you can start the moment you feel that familiar prickle.
Stage 2: blisters (days 2 to 4)
Over the next 48 hours or so, small fluid-filled blisters appear, often in a cluster.2 The skin around them can look red and swollen, and it may feel sore.
Try to leave them alone. The fluid inside carries the virus.
Stage 3: weeping (days 4 to 5)
Next, the blisters burst and release their fluid, leaving a shallow, painful sore. This is when a cold sore is at its most contagious.2
Gently keep the area clean. Wash your hands every time you touch it.
Stage 4: crusting (days 5 to 8)
The open sore dries out and forms a yellowish or brown crust. It can feel tight, itchy or cracked.
Keeping your lips moisturised can help stop the crust splitting. Leave it to come away on its own.
Do not pick or peel the crust. Reopening the sore slows healing and puts the virus straight back on your fingers.
Stage 5: healing (days 8 to 10)
The scab falls away and new skin forms underneath. The area may look a little pink for a while.
Most cold sores have cleared within 10 days.2 You're contagious until the skin has completely healed, so keep up the hygiene habits until then.2
When is a cold sore contagious?
The short answer: from the first tingle until the sore has completely healed.2 That covers every one of the cold sore stages, not just the ones you can see.
The risk peaks when the blisters burst and weep.2 The virus spreads through contact with the sore, saliva or the skin around your mouth, so kissing and sharing things that touch your lips are the usual routes.1
Oral sex carries a risk too. A cold sore can pass to a partner's genitals and cause genital herpes.2
Take extra care around newborn babies. Kissing a baby while you have a cold sore can lead to neonatal herpes, which is very dangerous for them.2
Not sure if it has fully healed? If there's any crust or broken skin left, treat it as contagious and keep your face away from babies.
How do you treat a cold sore at each stage?
Cold sores clear up on their own, but treatment can help them heal a little faster and feel less sore. Timing is everything here.
Antivirals, as a cream or tablet, can help a cold sore heal a little sooner and ease symptoms. They work best when you start them early. Zovirax Cold Sore Cream can also be started once a blister has appeared, so follow the instructions for your particular treatment.3 Once the blisters have burst, products that protect and soothe the skin come into their own.
Think of it in two phases: antivirals from the first tingle, then protection once the blisters have burst.
Antiviral tablets are prescription-only. A GP may suggest them if your cold sores are very large, painful or keep coming back.2 How often you take them, and for how long, depends on which medicine and dose you're prescribed, so always follow the instructions on the label.
If you get antiviral tablets through Pharmica, a prescriber will review your consultation first. This includes checking whether a GP, nurse or pharmacist has diagnosed your cold sores before, and whether the tablets are suitable for you. Start them at the earliest sign, and see a doctor if your cold sore gets worse or hasn't healed after 10 days.
Aciclovir
Aciclovir (sometimes spelled acyclovir) is an antiviral that stops the cold sore virus multiplying.3 That helps the sore heal sooner and can make symptoms less severe. It's the same active ingredient found in many cold sore creams, just taken as a tablet.
Valaciclovir and Valtrex
Valaciclovir is what's known as a prodrug of aciclovir. Your body turns it into aciclovir after you swallow it. It's absorbed better than aciclovir tablets, so you don't need to take it as often.
Valtrex is the original branded version of valaciclovir. It contains the same active ingredient.
Zovirax cold sore cream
Zovirax Cold Sore Cream contains the antiviral aciclovir. You apply it five times a day, roughly every four hours while you're awake, for at least four days. If it hasn't healed, you can carry on for up to 10 days. Still there after that? See a doctor.3 Like tablets, it works best started at the tingle stage.3
Only use it on cold sores on your lips and face. Do not use it inside your mouth, in your eyes or on your genitals.3
Dab it on rather than rubbing it in.2 It can briefly sting or burn after you put it on.3 Speak to a pharmacist if any irritation doesn't settle.
Compeed cold sore patches
Compeed cold sore patches are small hydrocolloid patches that sit over the sore and protect the skin while it heals.2 They're also fairly discreet. They don't contain an antiviral, so think of them as comfort and cover rather than a way to stop the virus.
Bonjela cold sore cream
Bonjela Cold Sore Cream forms a thin protective film over the sore while it heals. Like patches, it doesn't contain an antiviral.
How do you stop a cold sore spreading?
A few simple habits make a real difference while you have a cold sore:
- Wash your hands with soap and water whenever you touch the sore or apply treatment.2
- Avoid kissing and oral sex until the sore has completely healed.2
- Keep lip balms, cups, cutlery and towels to yourself.
- Never share your cold sore medication with anyone else.
- Try not to touch your eyes after touching the sore.
Your hands are the main route from the sore to everything else. Washing them often protects your eyes, your face and the people around you.
Want fewer cold sores in future? If sunshine sets yours off, a lip balm with SPF 15 or above can help.2 If they keep coming back, speak to a prescriber about whether antiviral tablets are right for you.
When should you see a doctor about a cold sore?
Most cold sores clear up without any fuss. Speak to a GP if:
- your cold sore hasn't started to heal within 10 days
- the cold sore is very large or painful
- you're worried about it, or think it might be something else
- you also have swollen, painful gums and sores inside your mouth
- you're pregnant
- you have a weakened immune system, for example because of a medical condition or treatment
If a cold sore appears near your eye, or your eye becomes red, painful or sensitive to light, get medical advice the same day.
A sore near your eye is not one to wait out. Same-day advice is the safe call, even if the rest of the cold sore seems mild.
Frequently asked questions
How long do cold sores last?
Most cold sores clear up on their own within 10 days. The first tingle usually turns into blisters within a couple of days, then the blisters burst, crust over and heal. Starting an antiviral cream or tablet at the very first sign can help it heal a little sooner. If yours hasn’t started to heal after 10 days, speak to a GP.
Can you stop a cold sore when you feel it coming?
You can’t always stop it, but you can often make it shorter and milder. Antiviral creams and tablets work best when they’re started as early as possible, ideally at the first tingle. If you get cold sores regularly, it’s worth keeping treatment at home so you’re ready to go.
Is it a spot or a cold sore?
A cold sore usually announces itself with tingling, itching or burning before anything appears. It then forms a cluster of small fluid-filled blisters, often on the edge of your lip. A spot tends to be a single raised bump that doesn’t tingle first. If you’re not sure which you’ve got, a pharmacist can take a look.
Are cold sore tablets better than cream?
Both can help. Antiviral creams and tablets can each help a cold sore heal a little sooner when they’re started early. The main difference is how you use them. Creams go on around five times a day for at least four days, and for up to 10 days if needed. How often you take tablets, and for how long, depends on which one you’re prescribed. Tablets are prescription-only, so a prescriber will check they suit you.
How can I get rid of a cold sore fast?
There’s no instant fix, but acting early makes the biggest difference. Start an antiviral cream or tablet as soon as you feel the tingle. After that, keep the area clean, dab creams on rather than rubbing them in and leave the scab alone. Cold sore patches can protect the skin while it heals.
Can I buy cold sore tablets over the counter?
No. In the UK, antiviral tablets such as aciclovir and valaciclovir are prescription-only medicines. You can get them from a GP, or from an online pharmacy after a consultation with a prescriber. Antiviral creams such as Zovirax are different and can be bought from a pharmacy without a prescription.
References
- World Health Organization. Herpes simplex virus. World Health Organization; 2026. who.int
- NHS. Cold sores. NHS website; 2026. nhs.uk
- Haleon UK Trading Limited. Zovirax Cold Sore Cream: Summary of Product Characteristics. Electronic Medicines Compendium; 2026. medicines.org.uk/emc
This article is intended for informational purposes only and does not replace professional medical advice. Always read the patient information leaflet supplied with your medication and speak to a healthcare professional if you have specific concerns.