Traumatic ulceration or Cancer.

Hello Sir I would like to know , is it the first time you have experienced this ulcer? As per the photos the last tooth is slightly tilted towards the cheek, as a result of which the sharp edges of teeth ( if there were any prior to grinding/enameloplasty) were in continuous contact with cheek, which lead to Frictional Ulcer. Give it some time, the ulcer might heal on its own. But mean while as you said its paining during regular mouth movements. You can apply Mucopain ointment prior to eating , it will numb the area required and you can eat without any discomfort. If the ulcer stays beyond 15days , kindly visit the Dentist. Also i would suggest to slowly quit tobacco or Atleast switch to Nicotex gums! Prevention is better than Cure♥️

Keep oral hygiene maintained, helps healing faster.

Avoid spicy food, avoid touching with hands, avoid alcohol and tobacco (delays healing)

It seems like traumatic ulcer . You can visit a dentist for coronoplasty to reduce the friction. You can use Rexidin M forte gel for 7 days If there is no relief , you should definitely visit a doctor.

Hello Looks like frictional ulcer Kindly get a physical consultation done once