How To Treat Small Red Rashes On Inner Thighs?

hello, I have had what I thought was a heat rash or possible stress rash,, if there is such a thing.. it is at the top inside of both of my thighs, they have been there for several months, started as a small red spot, but has since spread to a larger area and will not go away or even minimize.. there are no other symptoms, no itch, no pain, no bumps or any kind of texture, just splotchy discoloration. what could this be, and how can I get rid of it?