Hi.. Welcome to HEALTHCARE MAGIC.. I have gone through your query and can understand your concern... As per your complain and presentation of symptoms it seems your father is suffering from ORAL SUB MUCOUS FIBROSIS [OSMF] which is caused commonly due to tobacco chewing habit or in chronic betel nut chewers.. It leads to reduced mouth opening due to formation of thick fibrous bands inside the cheek mucosa leading to stiffning.. There is also burning sensation over the cheeks even on taking less spicy food due to atrophy [thinning] of the buccal mucosa.. Improvement in case of OSMF to tell you frankly is uncertain and there can be slight improvement to no improvement at all.. You should consult an Oral Physician and get him evaluated so that he can rule out the exact condition of your father and treat him accordingly.. The physician can advise him to take another course of steroid injections along with adding HYLURONIDASE as hyluronidase helps in breaking of the fibres.. Topical application of steroid ointment and hyluronidase ointment can help.. A numbing gel containing Lignocaine can be applied over the inner cheeks especially during eating to prevent burning and pain.. Mouth opening exercises can also be demonstrated that has to be done 3 to 4 times a day.. In case if he has any mal-habit of smoking, chewing tobacco or betel nut etc it has to be completely stopped.. In case if there is no improvement surgical approach can be planned to break the fibres but it can be decided only after thorough clinical evaluation and medical history of patient.. Hope this information helps.. Thanks and regards.. Dr.Honey Nandwani Arora..