Cold sore. They are the same. Caused by a virus.
My gf had a cold sore on her lips for more a month is it herpes? Becsuse I knew herpes sore heals completly after 14 days max
Stress. Those are caused by a herpesvirus, usually herpes simplex-1 virus. These blisters, which are highly contagious, may appear along with colds, fevers, exposure to excessive sunlight, certain medications, during menstruation or illness, but stress is probably the biggest trigger. Most of the time the virus will lie dormant in the body, but it can quickly come to life when your immune system is weak. Read more...