Difficulty opening the mouth after long-term tobacco use can be a sign of a condition called oral submucous fibrosis, where the tissues inside the mouth gradually become stiff and tight due to irritation from tobacco or areca nut products. This condition can cause burning sensations, reduced mouth opening, tightness in the cheeks, and difficulty eating or speaking. Stopping tobacco is the most important step, so quitting recently is very beneficial and can help prevent further worsening. Mouth-opening exercises, good nutrition, and avoiding spicy or irritating foods may help improve flexibility to some extent over time. However, this condition should not be ignored because in some people it can progress and may increase the risk of precancerous changes inside the mouth. An oral surgeon, ENT specialist, or dentist can examine the inside of the mouth properly and guide treatment options to improve mouth opening and monitor the tissue changes. If there are ulcers, white or red patches, pain, or rapid worsening, evaluation should be done as early as possible.