A cold sore usually lasts 7 to 10 days from the first tingle to fully healed skin, and most clear up on their own without treatment. The timeline runs through recognisable stages: tingling or itching for a day or two, then blisters appear, burst and weep, then crust over into a scab that eventually flakes away. Applying an antiviral cream such as aciclovir at the very first tingle — before blisters form — can shorten the outbreak, but it does little once the blisters are established.
Cold sores are caused by the herpes simplex virus (HSV-1), which most of us pick up in childhood and which then lies dormant in the nerves around the lips. It reactivates from time to time — often triggered by illness, sunshine, stress, tiredness or, for some women, their period. You cannot cure the virus or get rid of it permanently, but you can manage outbreaks and reduce how often they happen.
The stages of a cold sore
Stage 1: Tingling (days 1–2)
The warning sign. A tingling, itching or burning sensation around the lip, sometimes with slight swelling. This is your window: antiviral cream applied now, five times a day, can reduce the outbreak’s duration.
Stage 2: Blisters (days 2–4)
One or more small fluid-filled blisters appear, usually on or around the lip. They can be sore. The fluid inside is highly contagious, so don’t touch them — and if you do, wash your hands immediately.
Stage 3: Weeping (days 4–5)
The blisters burst and release fluid, then start to dry out. This is the most contagious phase. Cold sore patches (hydrocolloid plasters) are useful here: they cover the sore, keep it moist for healing, and make it less visible.
Stage 4: Scabbing (days 5–8)
A yellowish-brown scab forms. It may crack and bleed, especially when you smile or eat. Don’t pick it — you’ll slow healing and risk scarring or a secondary bacterial infection.
Stage 5: Healing (days 8–10)
The scab flakes off to reveal pink new skin, which fades to normal over the following days. The outbreak is over, but you remain contagious until the skin has completely healed.
What actually helps
For occasional cold sores, a pharmacist is your best first stop. They can recommend antiviral creams to speed healing, creams or gels to ease pain and irritation, and protective patches. Paracetamol or ibuprofen helps if the sore is painful. Keep the area clean, don’t share towels, lip balm or cutlery while you have one, and avoid kissing anyone — including, crucially, newborn babies, for whom the virus can be dangerous. The NHS guidance on cold sores sets out all of this clearly — see the NHS cold sores page for the full advice.
Because outbreaks are often triggered when your defences are down, general immune health plays a supporting role. Our article on how to strengthen your immune system covers the evidence-based basics, and if breakouts coincide with skin trouble elsewhere, how to reduce acne naturally may help too.
Preventing the next one
You can’t stop the virus reactivating entirely, but you can lower the odds. Use a lip balm with SPF 30 in sunny weather — ultraviolet light is a major trigger. Manage stress and get enough sleep, since run-down periods invite outbreaks. Some people find that arginine-rich foods (chocolate, nuts) coincide with outbreaks while lysine supplements help, though the evidence is mixed; it’s worth tracking your own pattern rather than following blanket rules.
Living with recurrent cold sores
If you get cold sores frequently — say, monthly or more — it’s worth being more strategic. Keep a tube of antiviral cream at home, at work and in your bag so you can start treatment within minutes of the tingle, wherever you are. Learn your personal triggers: for many people it’s a predictable combination, like sun exposure plus tiredness, or the week before a period. A daily lip balm with SPF 30, worn year-round rather than just on holiday, removes the single most common trigger for a lot of sufferers. Some people find that managing stress and getting consistent sleep stretches the gaps between outbreaks noticeably. And if outbreaks are very frequent or severe, ask your GP about suppressive antiviral tablets taken daily — they’re not for everyone, but they can dramatically cut how often the virus reactivates.
When to see a GP
Most cold sores never need a doctor. See your GP if outbreaks are very frequent, severe or unusually large, if sores haven’t started healing after 10 days, if the infection spreads to your eyes, or if you have a weakened immune system. Pregnant women who develop a first-ever cold sore near their due date should also seek advice.
FAQs
How long are cold sores contagious?
From the very first tingle until the sore has completely healed — typically the full 7 to 10 days. You’re contagious even before blisters appear, which is why early treatment and good hand hygiene matter.
Do cold sore creams actually work?
Antiviral creams like aciclovir can shorten an outbreak if applied at the first tingle, five times daily. Once blisters have formed, they make little difference to healing time — at that point, patches and pain relief are more useful.
Can I pop a cold sore blister?
Don’t. Popping spreads infectious fluid, increases the risk of bacterial infection and scarring, and doesn’t speed healing. Let blisters burst naturally and keep the area clean.
What’s the difference between a cold sore and a spot?
Cold sores start with tingling and form clusters of small fluid-filled blisters on the lip border; spots are single pus-filled lumps without the tingling warning. Cold sores are viral and contagious; spots are not.
Can you get rid of cold sores permanently?
No — once you have the herpes simplex virus, it stays in your body for life. But outbreaks often become less frequent and milder with age, and frequent sufferers can discuss preventive antiviral tablets with their GP.
