what causes to have a blister on your lips
Both cold sore and fever blister refer to the lip blisters caused by infections of the Herpes Simplex I virus (not to be confused with Herpes Simplex II, which is generally associated with genital herpes). Cold Sores are viral infections which cause recurrent groups of irritating, even painful blisters on the lips. The Herpes Simplex I virus affects more than half of the adult population, and over 50 million people in the US experience at least one cold sore outbreak per year.
After applying a menthol chapstick broke out with small water blisters on lips. Best thing : To do is stop using it. You may have become sensitized to it . If it is an old chapstick, and you don't wipe it clean after each usage, chances are, there is bacteria overgrowth and who knows what else.