Cold sores are a pain in more ways than one. They are ugly, of course, but for many they are numerous enough inside the mouth to cause difficulty eating and sleeping.
Cold sores are actually a viral eruption caused by herpes simplex - yep, that herpes, the one that can cause problems on any mucus membrane including the genitals and mouth. There are two strains of the herpes simplex virus. For a long time we thought type 1 infected the mouth