Hi.. Welcome to HEALTHCARE MAGIC.. I have gone through your query and can understand your concerns. As per your complain the symptoms of reduced mouth opening, lip thinning and burning sensation on eating chillies with a history of chewing tobacco is pointing towards a condition known as Oral Submucous Fibrosis [OSMF] in which there is formation of thick fibrous bands of collagen inside the cheeks and in advanced cases the bands are also seen over the inside of lips.. I would suggest you to consult an Oral Physician and get evaluated and a thorough clinical evaluation can help in confirming the diagnosis and treatment can be planned accordingly.. In case if OSMF is confirmed he can advise you to apply a steroid ointment on the inner cheeks to relieve burning sensation, hyluronidase ointment to break the cementing bond between fibres. Intralesional injections of steroid and hyluronidase can be given directly over the fibres under the skin. Antioxidant like Lycopene can also be advised.. Mouth opening exercises will be demonstrated that has to be done 3 to 4 times a day.. Avoid spicy food and take a nutritious diet.. Completely stop chewing tobacco as it can lead to oral cancer.. Hope this information helps.. Thanks and regards. Dr.Honey Nandwani Arora