What to do if i have a blister in my mouth and kiss somebody can they get it.?

What is the blister: If your "blister" is due to a dental abscess from a tooth or gum infection, the answer is no, it is not contagious. If the lesion is anything else than can be transmitted through kissing and sexual contact, then the answer would be yes. Since we don't know what this lesion might be, have it examined by a local dentist to see if it needs treatment.