Brief Answer: ORAL SUB-MUCOUS FIBROSIS. Hi.. Can understand your concern.. As per your complain difficulty in opening the mouth due to reduced mouth opening after the tobacco chewing habit is due to a condition known as Oral Submucous Fibrosis in which there is formation of thick fibrous bands in the cheeks leading to stiffening and reduction in mouth opening It is a pre cancerous condition so you should take care that you do not eat or smoke any form of tobacco again in order to prevent cancer. For the reduced mouth opening i would like to tell you that it is not possible to increase the opening like it was before and some improvement may or may not be seen with the treatment.. You should consult an Oral Surgeon and get evaluated and treated.. Steroids injections given directly into the lesions can help.. Topical application of hyluronidase containing ointments can help in breaking the cementing layer of fibres.. Regular intake of antioxidant capsules containing lycopene . Mouth opening exercises as will demonstrated by the surgeon should be regularly done.. If necessary surgical breakage of the fibres can be done but in some cases mouth opening is not increased due to scar formation. Hope your query is solved.. If you find the answer helpful please write a positive review and click on find this answer helpful as a token of appreciation.. Thanks and regards.. Dr.Honey Nandwani Arora.