You have to stop consuming tobacco immediately if you are looking forward to any permanent solutions . They are certain nicotine alternatives which are available in the form of gums to help you fulfill ur tobacco craving , you can opt for that and once u hv switched to them u can slowly withdraw that habit too . Temporarily u will hv to consume less spicy food , so that ur already irritated and worn out mucosa is not irritated more . There are certain exercises which help to tone back ur muscles and bring back ur mouth opening to normal . Depending upon severity if ur problem u may be have to take steroids injections and multivitamins. Cause of pain can be decay it tooth and gum disease too . Consult ur doc so that u can get a thorough examination of the tooth in concern .