herpes simplex
"I used to get cold sores four or five times a year, sometimes more often (especially when I was dealing with the stress of college). They would appear at the most frustrating times! I tried a bunch of alternative remedies, per the recommendations of friends and family, including L-lysine and tea tree oil. I even found myself putting nail polish remover on my lips (word to the wise: don't do that). Finally, I explained to a doctor how often I was getting outbreaks and how bad they were, and they prescribed 200mg of acyclovir a day as a suppressant. It didn't seem to do anything; the cold sores kept coming. Then, another doctor upped my dose to 400mg twice a day. I didn't get a cold sore for almost five years!"