Canker sore on my upper gum line, now there is a yellow blister on my lower gum line. what is it.. ?

See doctor: I would have to see the lesions to be sure that it is something benign. i usually give kenalog (triamcinolone) in oribase to put on these lesions so that you have relief while it heals.

CANKER sore: It could be another canker sore developing. Try to swish , then spit , with warm salt water . Eat a soft, bland diet until the sores are healed. There is also, over the counter medication to help heal canker sores.

Get checked: Best to get an exam because of how different blisters vs sores look. It could very well be just an ulcer which can heal with time. Please get checked for a more thorough and proper diagnosis.

Herpes virus: Canker sores and cold sores are often caused by a herpes simplex 1 virus, HSV1. This is a very common virus causing sores around the mouth. If the sores are very frequent talk to your doctor about testing and possible medications to avoid frequent breakouts. This is a similar but different virus from HSV 2 which is genital herpes.