Is this cancer? Increased. please help!

1.5/2 months back i had a dark pigmentation found in right buccal mucosa, i showed it to dentists they said its physiological pigmentation, I went for clinical examination with an ent and other dentist too, they saying its normal, but i had only on right now it's increasing in left buccal mucosa as well as under upper lip mucosa, i am really scared. It doesn't hurt itch or burn, only feel a little weird, when i sleep on sode or say smile, when it gets rubbed with teeth feels a little rough and when lingered with tongue, it feels like granular/rough patch, i dont smoke or do tobacco, also i have observed this post taking covaxin frst dose, idk if that caused that or it was before that... please help me! I am really scared :(.. As prescribed by doctors i have tried applying topical steroids, it reduced it for a while but when stopped increased... please help!!