What could this be?

I have a circular dry scab on my scalp thats gotten bigger overtime and only grows in this same spot. The rest of my scalp is clean and healthy except for this area. My boyfriend thinks its dandruff and my bestfriend thinks its a scalp fungus. Everytime I remove it or moisturize/ wash the area it comes back in a couple days. It's also causing my hair to bald in that area only. I can't afford to go to a doctor. Any over the counter suggestions?