i have a blister kind of thing on my lower lip at the moment, it doesn t hurt, its smallish to medium size, it is a yellowish color with a bit of white, but it kind of blends in with the color of my lips, i think it may be a cold sore/fever blister, but not sure, i know it is not a canker sore because i read online that canker sore hurts to the touch but i m not sure if that information is credible. can any one tell me what it is and how i can treat it.