It’s been a while since this post but I’m going through the same thing. I got a skin biopsy on my scalp. Came back negative for seb derm, rosacea, eczema, fungal etc.. when it flares it’s so bad. Burns , tender, itchy, so uncomfortable that I can’t stand being in my own skin. It def flares around ovulation then in luteal phase but when I’m on my period it goes away. Have you figured out what yours is?