Hello
Hello, I have gone through the description provided by you and would help you out. If its size is decreasing it could be the blister because of hot food. Is it bleeding or getting pain? If it is accompanied by bleeding it can be gingival or periodontal problem.(related to gums and tissues surrounding tooth)If it is accompanied with pain along with bleeding or pus then it could be a gum abscess and if the teeth are seems to lose then it could be periodontal abscess. If the teeth are carious in that region then it can be Chat Doctor. So the conformation can be given on checking the region. Best advice would be consulted with the dentist. Until then, you can do following thing