I can't stop picking and scratching

KK

In person it's so much worse. It's red and there are so many more spots. This is the back of my neck. Everyday for the last few weeks I cannot stop picking under and in my hair line. At first it started because of little bumps but now it's just because of me. I teach second graders and I'm so scared that one if going to ask what's wrong with me if I put my hair up. I don't know how to stop. I do it without even realizing it. Please help!