Suggest Treatment For Rashes In Under Arm And Bikini Line

I have been getting an awful rash in my underarms and my bikini area where I shave. I've tried over the counter acne scrubs and soaps to get ride of it. I've tried changing razor blades and deodorants. Nothing has worked and it is getting worse. I've recently noticed scaring appearing. What could the problem be and how can I fix it.