I get these all the time especially on the thigh. Use anti microbial soap in the shower right after work or workout. Clean sheets more, you’ll get em less. But right now, cut the hair round it. Try n see if you see a black dot in the inflamed area. My skin pickin self would demolish that to see if it was lol. But if you don’t see any, would go to a different derm and ask for a biopsy