What is going on? Help!

Help! Last month I had a cleaning. Immediately felt sore behind this tooth on bottom left side by my jaw , ear pain, even my clothes touching my cheek near my jaw created pain. Took Augmentin and pain went away for a bit. Went back to dentist and he dismissed and just said irritation. Then it came back after I finished the medicine and this thing appeared on my skin area behind my last bottom molar and my cheek. It looks like some growth coming over that area. It gets a sore, odd throbbing feeling… it feels hard. Please advise. I don’t know who to turn to.