She most likely has a cold sore. Cold sores are contagious while they are visible. It is not very likely that you could acquire a cold sore if you kiss her while her lips look fine. Do not kiss her while she has a cold sore. Cold sores are harmless, however they are highly contagious to others as well as yourself. If you have a cold sore and touch it, you can potentially spread it to other areas of your body. If you really like this girl don't let a little blister freak you out. Tons of people get cold sores and it does not mean that she is gross or diseased. If you really want to kiss her just make sure she doesn't have a sore. Besides, cold sores hurt pretty bad so I doubt she'd want to kiss you with one on her lips anyway.

Thanks

dave

Well I have never once had a cold sore/fever blister and my fiance gets them ever once and a while but never passes them to me...And I even kiss him when he has them...

I think it's possible but highly unlikely if it is healed. I can give you a bit of useful info where fever blisters are concerned, and that is to not go down on anyone nor let anyone go down on you if they have a fever blister or sore on their lip because you most definately can get genital herpes as a result even if your partner doesn't have the genital kind.