For the past 4 years I’ve had recurrent tiny water blister type things on the gum behind my top left wisdom tooth. There is only ever 2 or 3 of them and they come and go, and only last from a few hours to 24 hours. I’ve tried to show them to the dentist, but by the time I get to see him they are gone. I feel that citrus fruits aggravate them. I don’t have them anywhere else in my mouth. They can be gone for months at a time. They aren’t painful, but they are annoying and I am aware of them as they feel a bit raw. Does anyone know what these could be? The dentist says the skin in that area looks fine, but because he hasn’t seen the blisters, can’t tell me much more.