Red marks in mouth. Rd time in 45 days!

Hi Lately I have been having a little discomfort related to some red marks in mouth. So I've noticed that I'm not really having an ulcer or a blister but the upper layer of the skin gets rubbed of or dries up and then it recovers in 1/2 days but there is a very small red color mark which remains. It is completely painless and it doesn't feel like a bump or hard. It's just like the skin seems more sensitive when felt by tongue and is very slightly red. First occurrence was in inner cheek and this next is under the lip. I showed it to one ent and he said it's nothing. The upper skin coming of seems more like how the upper layer of the finger would come off and come back again. It's painless and is not water filled or white or yellow. It just looks like the top skin comes off. Happening 2nd or 3 rd time in 45 days