What Does An Itchy Brown Rash In Upper Thighs Indicate?

I had sex 1 time and that is when I lost my virginity 3yrs ago.... 8months ago in my upper legs close to my private but the side iny my legs I got brown stain with pimples shape like a circle And the pimples goes away for 3-4days and comes back and makes brown stain. I don t feel itchy but when I touch It i get itchy, sometimes I feel like it s poking me I dont know why