herpes simplex
"I have had cold sore all my life, and usually get them 1-2 times a year until I found Abreva about 8 years ago.  It worked well for me, put it on a soon as i felt the tingle and the sore would never develop .  However the past three times that i had a cold sore it did not help at all.  the really weird thing is that the last three that i got came with no warning.  i would wake up in the morning and boom it is already on my lip and developing.  This one lasted for 8 days, i am planning to talk with my doc about something stronger."