What should i do if i have a blister below my lip?

Depends on the cause: There are many types and causes of skin blisters or rashes. Several types of inflammatory conditions of the skin, allergic reactions, and sometimes bacterial, viral or fungal infections and insect bites can cause blisters on the skin. Have it evaluated by a professional and get the appropriate treatment.

Ointments: Bismuth subsalicylate (kaopectate) may protect raw mucosa and accelerate healing. Multivitamins with iron are sometimes recommended but do not have any clear benefit. Your physician may give you an antiviral cream called zovirax and sometimes pills called Valtrex (valacyclovir) to shorten the duration of the symptoms if caught early. Alternatively 1% Hydrocortisone cream over the counter can reduce inflammation.