Since 1-2 weeks i felt that in right side of my inner mouth/cheeks, theres a dot dot pattern feeing(just like it happens when cold or something happens), i dont have cold not and flu. Today I saw the inner cheek has turned black, i dont smoke, drink or eat tobacco. I am scared why this has happened, please help me! When I touch that with tongue it tastes soury and there's no pain. Why is this happening? I am scared. I have attached photos, please help me! I had a dental filling last month, could that have caused it? Please help me!!