Hi..No need to worry because it's not cancer. It's a keratotic area which appears white because of friction. It's also called as frictional keratosis. It may a lichen planus lesion also. But no need worry in either of these cases as these are just normal variations. Please visit a nearby dentist to get smoothening or polishing of the irritating crown. And application of the gel if needed. Regards

Hi as it looks need not to worry..may be caused due to irritation from crown ...visit ur dentist to check ne traumatic irritation from crown..best of luck take care

Hello, I understand your feeling. Well we thank you for giving a proper history. Since you have dental crown sometimes that may irritate your tongue mucosa and it may form in to ulcer and present as a white patch. Cancers does not occur without any prior cause. So you don't need to worry. An ulcer takes 7-10 days to heal. Just keep taking b complex tabs for 3 more days and stop after that. Thank you