How To Prevent Fever Blisters?

What are fever blisters?

Fever blisters are commonly known as cold sores. They present as tiny, fluid filled lesions or swellings called blisters that appear on the lips, under the nose, around the chin or other areas of the face. These blisters usually occur in groups and they cause sore, red and swollen wounds which usually last for about a few days to weeks and are very contagious.

However, fever blisters are often confused with canker sores but they are quite different. Canker sores are whitish or yellowish sores which are usually painful and form inside the mouth only. They mostly appear on the tongue and insides of the lips and cheeks and they are not contagious. 

What causes fever blisters to appear?

Fever blisters are caused by a common and contagious virus known as type 1 Herpes Simplex Virus (HSV-1). The Herpes Simplex virus is categorised into HSV type 1 and type 2.  HSV-2 is only transmitted sexually and is the cause of  genital herpes. The  HSV-1 virus, which is the cause of oral herpes (herpes labialis), generally resides in the nerve cells in the body where it may become reactive, travelling to the skin and as a side effect gives rise to an area of inflamed skin around the mouth, or other areas of the face, in some cases. 

According to WHO, about 67% of the population are infected with HSV-1 which is usually acquired during childhood and mostly remains asymptomatic and only manifests through recurring blisters around the mouth.


Certain psychological and environmental factors such as stress, cold, fatigue, exposure to excessive sunlight or wind can trigger the occurrence or recurrence of fever blisters.  Diseases that compromise the immune system such as HIV or other viral infections, as well as hormonal changes such as those related to menstruation, can also be a trigger for the appearance of fever blisters.

Where do you get fever blisters?

People get these blisters on the outside of the mouth and around the  lips, under the nose or around the chin, in most cases.

What does a fever blister look like?

Fever blisters can be seen as tiny fluid-filled swellings mostly appearing on the border of the lips or other surrounding areas of the face. Mostly, they occur in groups and can result in the appearance of red, sore and painful wounds in the affected regions. They may release a clear fluid and then crust over after a few days, and it is in this period that they are most contagious. 

Are fever blisters contagious?

 Fever blisters are contagious and are mostly so when oozing liquid because the virus can be spread easily through contact with infected body fluid. Fever blisters can be spread from a person to another through kissing, sharing items like cups, spoons, water bottles, chapstick or lipstick or other items that come in contact with the lip or face. 

How long will a fever blister last?

Fever blisters appear and form within a day or two, after which they break and ooze. They then form scabs that last for several days until they eventually get healed in about two to three weeks without leaving any scar. 

How to prevent fever blisters

Cold sores or fever blisters can be prevented by 

  • Avoiding kissing and having skin contact with people who have blisters
  • Avoiding sharing personal items especially those used around the lips and face
  • Applying a lip balm on the lips to protect them from the sun
  • Keeping the hands clean always
  • Staying healthy and getting enough rest. Fever and fatigue can weaken the immune system and thus make you susceptible to  them
  • Reducing stress
  • Sunscreen: Applying a sunscreen helps protect the face  from the rays of the sun thereby preventing the incidence of blisters

What increases your risk for fever blisters?

Risk increases for fever blisters include 

  • Cold or fever
  • Diseases like HIV or other viral infections as well as other health conditions that compromise the Immune system
  • Hormonal changes such as those associated with menstruation
  • Physical injury
  • Some medications

Natural home remedies for fever blisters

Studies show that certain essential oils may have antiviral effects against HSV-1. However, it is important to know that essential oils can irritate your skin and so should be diluted with carrier oils before use.

Clean cotton swabs should be used to apply the oils to prevent reinfection due to contamination. 

Listed below are some home remedies for fever blisters:

  • Ice: Wrap an ice pack with a cloth or towel and place it on the blister. This helps to reduce inflammation by reducing blood flowto that area. It gives it a numb feeling and less pain is felt as a result. However, you should know that this remedy is only temporary and doesn't affect the virus in any way
  • Oregano oil: This essential oil has been proven to contain properties that inhibit various human and animal viruses including Herpes Simplex Virus
  • Tea tree oil: Studies suggest that tea tree oil may be relevant in speeding up the healing process and preventing plaque formation. It should be applied topically by adding diluted oil to a cotton wool then dabbing over the sore several times daily

Prescription medication for fever blisters

Generally, cold sores clear up even without treatment within two to four weeks at most. Over-the-counter pain relievers can be taken to help manage the pain.  Also, there are several types of prescription antiviral medication  which may speed up the healing process. Some of them include 

  • Penciclovir (Denavir)
  • Acyclovir (Clovirax)
  • Famciclovir
  • Valacyclovir (Valtrex)

Creams such as docosanol (abreva) can be applied to the sores several times daily for treatment but the pills work better than the creams, generally. 

When to see a doctor

If you're suffering  from or recently suffered from fever blisters, you should see a doctor if you experience the following:

  • If you have a weakened or suppressed immune system
  • If you're not sure if it's a fever blister
  • It doesn't go away over a period of weeks
  • If you develop high fever that persists over time
  • If you have frequent  recurrences of fever blisters


Fever blisters, or cold sores, are small, contagious blisters caused by the herpes simplex virus type 1 (HSV-1). They appear on the lips and face, triggered by factors like stress and sunlight. They last for about 2-3 weeks, but can be prevented by avoiding contact and sharing personal items. Home remedies like ice and essential oils may help, while prescription antiviral medications can speed up healing. Consult a doctor if blisters persist, recur frequently, or if there are accompanying symptoms like a high fever or weakened immune system.


  1. Natural Fever Blister Remedies, Causes, and More.” Healthline, 25 July 2022,
  2. Cold Sore - Symptoms and Causes.” Mayo Clinic, Accessed 21 Nov. 2022.
  3. Accessed 21 Nov. 2022.
  4. Fever Blisters & Canker Sores. Accessed 21 Nov. 2022.
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Aisha Adeyiga

Bachelor of Science - BS, Anatomy, University of Ilorin

Aisha Adeyiga is a graduate of Human anatomy. She's enthusiastic about medicine, health and wellness. She loves to read books and travel.

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