I can’t believe they didn’t give you something to put on this area to try to get it to heal up.. I would either go back to the dermatologist or back to your primary doctor and say help
There could be a few things that was causing it that needs to be treated
Or your body is reacting to something you are using daily.
Be your own detective did you start any new shampoos soaps, lotions makeup, and so on just before they started?
Do your own documentation so you have that when you get back to the doctor as what is going on and take a picture or two on your cell phone?
This has been going on way too long and you need answers
I wish you the best figuring this out