The first thing that you need to do is to quit the habit that you have realised is causing this problem. Going by the description that you have mentioned it seems that you are suffering from Oral Submucous Fibrosis. A clinical examination will be required to access the grade of the condition so that appropriate treatment options can be explained to you. None of the treatment modalities known for this condition till date are hundred percent effective so the best options in your case can be explained only according to the case. There is no medication as such which can cure this problem although antioxidants are described as a supportive therapy. Regards.