Herpes Simplex
"Does not work at all!!!!!!!!! I started using Abreva at the first sign of a cold sore and less than 4 hours  later I had a small bump appear. I was using Abreva all day but by bedtime ( 12 hour&#039;s after I first applied ) I had a full blown cold sore. 2 days later and now my whole top lip is broke out. I washed the area and used Q tips to apply but for some reason it still spread. I have never had one to spread before so I will never use this again. I will just stick with tea tree oil."