Get it extracted

This is called as cheek bite. It's due to partially erupted wisdom tooth in the mouth and also when teeth is titled towards cheek this problem arises. The best treatment options is to visit and oral surgeon who will advise some x rays following which both the upper and lower wisdom teeth should be removed. In the meantime application of pain relief ointment/ or tablets might lessen your pain. But that's just a temporary, not a permanent solution.

Your symptoms are due to the condition called as pericoronitis and the only permanent solution is the removal of the offending tooth. Medications or home remedies will only provide temporary symptomatic relief and the symptoms are bound to reappear. An x-ray will be required to access the condition of the bone and the root and the extraction can be planned accordingly. Please consult an oral surgeon for the same. Regards.