It’s easy to get them confused, but cold sores are not the same as canker sores. Cold sores are red blisters that appear on the lips as a result of infection with the herpes simplex virus. They almost never occur inside the mouth and they are not associated with gum disease. By contrast, canker sores, which are not associated with herpes or gum disease, almost always occur inside the mouth.
Usually, cold sores last for seven to 10 days, after which time the pus-filled blisters will rupture and ooze. Fortunately, cold sores usually heal without leaving scars. Most cold sores will resolve without treatment, but you can apply a topical medication such as lidocaine or benzyl alcohol to relieve pain and itching.
If you develop a cold sore, avoid skin-to-skin contact. And don’t share razors, eating utensils, or towels—those are other ways the infection spreads to other people. If you have frequent cold sores, or a cold sore that doesn’t go away after seven to 10 days, talk to your doctor.
It can be hard to reduce the risk of cold sores, but it certainly won’t hurt to maintain a consistent personal hygiene routine including regular hand washing. Also, using a lip balm with sun block throughout the year, not just during the summer, can help prevent cold sores, too.