How to Identify the Signs of a Cold Sore: Everything You Need to Know

Cold sores are blisters (sometimes called‌ Herpes Labialis) that develop on the edge of your lips and are caused by a contagious virus called Herpes Simplex 1 (HSV-1). If you think you have developed a cold sore, don’t worry, you are not alone. Around 3.7 billion people aged 49 and under carry the Herpes Simplex 1 virus (HSV-1). Once you have a cold sore, the virus lies dormant in the nerve endings. Unfortunately, it can reawaken in the future, causing another cold sore. 

The dormant virus can crop up when you are ill, have a menstrual period, have had a dental procedure that caused trauma to the area, or even if you are stressed. Exposure to excessive sunlight can even bring about another cold sore! Usually, the first time you have a cold sore is the most uncomfortable. Subsequent outbreaks are typically less severe.  

Cold sores are annoying, uncomfortable, and not the most attractive addition to your lips. There is good news, though. A cold sore will go away on its own in 10 - 14 days, and there are remedies you can use at home to get you comfortably through them.

What Are the Common Symptoms of a Cold Sore?

Usually, cold sores appear on one side or corner of your lip. A small blister or a grouping of blisters with pink or red swelling around them will pop up. The sores can sometimes spread inside your mouth, known as the mucosa, and on the skin around it. There are five stages, from the initial onset of a cold sore to its eventual healing.

  1. You may feel a tingling on the edge of your lip up to a day before the first blister appears. 
  2. A fluid-filled blister or group of small fluid-filled blisters will appear around your mouth.  
  3. In the next stage of the breakout, the blister will open and leak. The cold sore may sting when in contact with acidic foods such as ketchup, tomatoes, citrus juices, or anything spicy. 
  4. Next, a crust or scab will form. During this time, the sore may be dry and crack easily if you yawn or laugh, causing a small amount of bleeding. 
  5. Soon the crusty scab will fall off, and your cold sore will be healed.

Remember that HSV-1 is contagious while you are experiencing a breakout or an active cold sore. Avoid physical contact with others when you have a cold sore. Don’t share drinks, utensils, or food; wash your hands well. Do not touch the sore. And no kissing!

How Can I Tell If I Have a Cold Sore?

Have you developed a small blister or a group of small blisters on the edge of your lip?

Within the past 24 hours, did you feel a burning, itching, or tingling in the spot the blisters are showing now? 

Have you had a cold sore before?

If you answered yes to any of these questions, there is a chance you have a cold sore. It is easy to come in contact with the virus that causes cold sores (Herpes Simplex 1, or HSV-1). 

Have you interacted with another person who had an active cold sore? You may have innocently shared a drink or utensil with someone that is completely unaware they have HSV-1. You may have contracted the virus some time ago, and this is your first breakout.

HSV-1 spreads so easily that it is almost impossible to know where or when someone is infected. The virus can lie dormant for years before becoming visible as a cold sore or, in some people, never show as a cold sore at all.

Can a Cold Sore Spread Through Contact?

So many people have HSV-1 because it is an exceptionally infectious virus. Cold sores spread easily from person to person during breakouts until the sore completely heals. If you have an active cold sore, following the advice listed below will reduce the likelihood of spreading HSV-1 to others.

  • Wash your hands regularly, and do not touch your cold sore.
  • Refrain from kissing anyone. Even a peck on the cheek or top of the head can pass the virus on.
  • Physically distance yourself from people with weakened immune systems, like older adults, sick friends or family, or newborn babies. It is crucial to stay away from newborns during an outbreak, as they can contract a much more severe infection from HSV-1.
  • Don’t share your lip balm, towels, or razors, and don’t use anyone else’s.
  • Don’t share food, drinks, plates, or utensils with anyone.
  • When your cold sore has resolved, replace your toothbrush, toothpaste, lip balms or lipstick, and anything that has come in contact with your cold sore.

Are There Any Home Remedies I Can Try for a Cold Sore?

You can use these remedies at home to help you through the progression of a cold sore:

  • Over-the-counter medications containing benzocaine and L-lysine applied to your blister can keep it moist and more comfortable.
  • Creams like Docosanol, when used as soon as your symptoms appear, may shorten the duration of your cold sore.
  • Using ice on your blister can relieve the pain.
  • Wearing sunscreen and avoiding sunburn can help keep your cold sore protected and moist while outside.
  • Avoid acidic foods like tomatoes and drinks like citrus. The juices from these foods sting on contact with cold sores.

Now You Know What to Do with Cold Sores

No one enjoys having a cold sore. They are uncomfortable and don’t look very enticing. It is almost impossible to cover them up. Cold sores do, however, go away in a relatively short period. Using easily obtainable remedies can help you feel more comfortable, and before you know it, your cold sore will be gone.


American Academy of Dermatology Association. (n.d.). Cold Sores: Overview. 

Kaye, K.M. (2022, September). Herpes Simplex Virus (HSV) Infections. Merck Manual Consumer Version. 

National Library of Medicine, National Center for Biotechnology Information. (2018, July 12). Cold sores: Overview. 

World Health Organization. (2023, April 5). Herpes Simplex Virus.,main%20cause%20of%20our%20 herpes


Kate Houck

Nurse Bio:

Kate Houck, RNC-OB

Kate is a L&D nurse with 9+ years of experience in OB, lactation, school nursing, and pediatrics. She has a passion for taking care of families and helping new nurses be the best they can be.