Since you mention your habit of chewing Tobacco-products, then the probable implication is that you have already consulted a doctor, and you know that your problem is OSMF (Oral sub-mucousal fibrosis
), and not any TMJ
(Temporo-Mandibular Joint) problem. DO NOT CONSIDER ANY SURGICAL OPTIONS, as after radical ressection (surgery for OSMF), more chances are that your mucosa may contract even more than at present state, when it heals over the surgical scars
, making your mouth close even further. Your best option is to completely quit Tobacco consumption (in any & all forms), considerably reduce and limit the use of spices in food (bland food would be best though), completely avoid all mucosal irritants like Alcohol, Soda, Aerated Drinks, Vinegar etc., & stay on a diet of fresh fruit and vegatables, for no less tha 6-9 months. Antioxidants
& Physiotharapy will help, for which you should seek proper medical help
from a good Hospital or Medical & Dental college, but be assured, that once OSMF sets in, it can never be properly cured, but only further degeneration can be stopped, if properly intervened and tackled in time.