Valacyclovir
"Ok, I've done everything in my power as a human to prevent and mitigate cold sores.  If someone told me that radiation would help, I would have done that, so when my doctor recommended Valtrex, I was on board.  He said the next time I get one, to come into the dermatologist office to confirm and then he would prescribe it to me.  Naturally, I got one on a Friday and had to resort to the walk in clinic.  I got the perscription 1 g/d for 5 days.  I then promptly changed it to two 2g dosages for 1 day as per a clinical study.  So far, I know it is helping.  Blister didn't just go away or anything, but the infection is calming down and I think it will heal much quicker.  It is worth it if it at least stops it from spreading."