I Have Developed A Rash And Inflammation Around My Mouth

I have developed a rash and inflammation around my mouth and chin area. I have had dentures put in around a year ago. Have had much trouble w/bottom plate fitting correctly and developed angular chellitis. Prescribed nystatin and gone in 2days. I've since tried hydrocortisone valerate f/several days w/this new rash nod is seemingly getting worse. I'm at a loss.