Red mark under lip

I am a 26 year old male. I have this red mark under the right side of my lip for about a year now. I have been to the dermatologist twice. First time he said it was dermatitis n prescribed me Desonide ointment 0.05%. I used that religiously for 2 weeks and nothing. Went back and he gave me some cream that had 2% Ketoconazole and 1% Hydrocotisone. I been using that for over a week and also nothing. Over the span of about a year the mark went away once for about a week but came back. Sometimes it flakes but never itches. It also varies in redness.  There seems to be a smaller one developing on the left side.  I don't drool in my sleep either.  Please help!