Yellow roughness on inner cheeks. Bm!

2 mouth ago, I came accross a small patch on my left side of inner check. As time went by it started growing and it was on both side of my cheeks and it had redness around it which was sour to taste! (Note. I used to constantly touch it with my tongue!) Then I consult a dentist he said it's just a discoloration nothing to worry about. I was still worried so i consulted my family doctor and he gave me Bi-Folate tablets Kenacort to apply on the affected area, D-soft tablet, and told me not to irritate it with my tongue as time went by it reduced but when i stop applying Kenacort it feels like it is coming back!  Note;1. I have a upper wisdom tooth to my left side not sure if that's the reason why I have the roughness Note2. I don't smoke nor i have any other habit. I do drink but occasionally, i am very much tensed about it i hope it is not Cancer! Please help. Attached image. 1 left BM 2 right BM