Hi Dear, Welcome to HCM. Understanding your concern. As per your query you have symptoms of grey and black spot on the inner cheeks which are pointing towards a condition known as leukoplakia and it could be due to hyperpigmentation of skin. Need not to worry. Mild leukoplakia is usually harmless and generally resolves its own. Usually in case of leukoplakia spots are white to grey in color, however due to changes in oral cavity environment sometimes they turned into red which also appear black sometimes . So I would suggest you to consult oral pathologist for proper evaluation of the condition and go for examination like FNAC to rule out cause like cancer. You should quit smoking if you does and you should maintain proper oral hygiene. You should do warm saline rinses regularly . Hope your concern has been resolved. Get Well Soon. Best Wishes, Dr. Harry Maheshwari