Cold sores are caused by the herpes simplex virus, which is believed to lie dormant in certain nerve cells of the body until it is activated by stress, anxiety, a cold, or excessive exposure to the sun. The sores last anywhere from 7 to 14 days.
Although some use the terms "cold sore" and "canker sore" interchangeably, they are different. Unlike cold sores, canker sores are bacterial infections inside the mouth that are characterized by small, round, white areas surrounded by a sharp halo of red. And, while cold sores are highly contagious, canker sores are not.
Unfortunately, attempting to camouflage a cold sore with makeup often aggravates the problem. Still, while you can't do much about the way a cold sore looks, you can do a few things to help decrease discomfort, speed healing, and keep it from coming back. You can even take steps to prevent passing on your cold sore to others. Here's how.
Protect your lips from the sun. Applying sunscreen to your lips may help prevent sun-induced recurrences of cold sores. Look for a sunscreen designed especially for the lips that has an SPF of 15 or higher. Or, choose a lipstick that contains sunscreen.
Keep it to yourself. Cold sores are extremely contagious. Avoid kissing and sharing cups, towels, or other such items. Wash your hands frequently, especially after touching cold sores. And take care not to touch your eyes or genitals immediately after touching cold sores.