Cold Sores (Herpes Simplex Virus)

The herpes simplex virus causes fever blisters or cold sores. Fever blisters are small sores on the lips, gums or roof of the mouth. People commonly get infected with this herpes virus but do not have any symptoms. The blisters may break out when a person:

  • Is especially tired.

  • Has a fever.

  • Is menstruating (in women – having a monthly period).

  • Under emotional stress.

  • Has another infection (such as a cold).

  • Is exposed to sunlight.

Pain, tingling, itch, burning may occur before the blisters in the affected area. The blisters usually heal within a week. The virus can be easily passed to other people and to other parts of the body such as the eyes and sex organs.


  • Only take over-the-counter or prescription medicines for pain, discomfort, or fever as directed by your caregiver. Do not use aspirin.

  • Do not touch the blisters or pick the scabs. Wash your hands often and do not touch your eyes without washing your hands first.

  • To help reduce discomfort, apply an ice cube or ice pack to your lip for 30 minutes or suck on frozen juice bars.

  • Use a sun screen on your lips when you go outdoors.

  • This infection is contagious. Avoid close contact with other people, especially kissing or oral sex, until blisters heal. The virus that causes cold sores usually is different than the one that causes sores on the genitals. However, cold sores may occur in persons who have oral sex with a partner who has genital herpes.

  • Hot, cold, or salty foods may hurt your mouth. Use a straw to drink. Eating a well-balanced diet will help healing.


  • Your eye feels irritated, painful, or you feel like you have something in your eye.

  • You develop a fever, feel achy, or see pus instead of clear fluid in the sores. These are signs of a bacterial (germ) infection. You can apply over-the-counter neomycin ointment.

  • You get blisters on your genitals.

  • You develop new unexplained symptoms.


  • Understand these instructions.

  • Will watch your condition.

  • Will get help right away if you are not doing well or get worse.