DANDRUFF OR DRY SCALP?

Y’all I need HELP!!! I have bad dandruff or dry scalp I honestly don’t even know 😩 I can’t even move my hair without it falling out and I ta so embarrassing! I only wash my hair every other week. I honestly don’t know what to do anymore. I’ve use tea tree oil shampoo, head and shoulders. But I’m stuck. It itches so bad I have sores ALL ON MY SCALP!! It makes people think I have lice or something. Someone please help 😭 it is so uncomfortable.