How do you use Abreva for a cold sore?

Apply a thin layer of Abreva to lips at the first sign of a cold sore five times a day, or every three to four hours, says WebMD. If the cold sore is not yet present, apply Abreva to the area of the lip that is tingling, swollen or irritated.

Abreva is a brand name for the medication docosanol, states WebMD. It is used externally to treat cold sores and fever blisters, or herpes labialis. The medicine stops the herpes simplex virus from spreading to healthy skin and may speed healing of cold sores. Abreva does not cure cold sores or stop the transmission of the herpes simplex virus to others.