What Causes Bald Patch And Burning Sensation On The Scalp?

am having a terrible problem with my scalp and cannot find a doctor to help me. I cut my hair so the bald spots and stunted hair growth on the top of my scalp woudl be obvious ... and they are. It is almost like a reverse mohawk with short, stunted hair down the center of my head. The bald spots hurt beneath almost like they are nailed to my head. My scalp feels tight around my head and it feels like there is a buildup of some type under the hair area but of course above the skull. Last fall I had scabbies on my arms and legs ... very painful. I had THREE occurrences where when showering and rubbing my scalp trying to reduce the "build up" sensation (and itching), that something (not visible) seemed to drop onto me from my head. The burning sensation was unspeakable. Like a hot poker. It resulted in whelps which, when examined closely almost looked like a series of tiny scooped out areas and also individual bites with a generalized reddening of the area. I have ended up in the emergency room with this. I am totally preoccupied with this problem and in dire need of help from a medical professional who is committed, patient-centered and intellectually curious. What I have is apparently unusual. The two dermatologists I have been to say I am "imagining" my problem because biopsies were unremarkable... I could understand that if I didn't have so many obvious physical symptoms ... which are documented in photos. I am wondering if the scabbies are under the hair. I can sometimes feel a sensation and admit I'm horrified at that possibility. Please help me.