Hey. I keep getting a swollen left cheek, which is causing me alot of discomfort and pain its also visible to see. I have had it several times but each time gets worse for some reason? Last time it got so big i went to the hospital where they put me in a private room thinking it was mumps  how ever it wasnt and was later on given penicillin ( 7 day course. ) and it did eventually go, however it keeps reoccurring. Its definitely not dental as i have been to a dentist what is it?  If it helps, im 18 and a female.
Welcome to Chat Doctor forum. Any short term swelling over human body is mostly related to an inflammation. As you have a painful swelling over back side of the lower jaw and the possibility of Mumps is discarded and that is reduced by Penicillin, then the swelling must be from an inflammation due to infection of some localized structure. The source is mostly from the oral cavity as the other structures like muscles, cheek soft tissue, skin or bone does not get inflamed or infected without an infection source or from trauma. I do not know what your dentist said, but the most common cause of such kind of painful swelling is from Impacted third molar tooth as you have stated that you have no other dental problems. Your dentist should take an OPG(a kind of full mouth radiograph) and hopefully find the source of infection or probable cause of inflammation which causes your facial swelling. Regards.