Valacyclovir
"I pop one of these, "Valtrex" 1grm and not long after I notice a change in my cold sores.  AND I GET THEM BAD.  ....so bad that I can't eat things like chips, salty things, candy, etc. It's miserable.  If Valtrex didn't exist, I would be in quite a lot of pain and discomfort.   I carry extras in my locker at work in case an outbreak hits again."