How To Treat Itchy Sores Behind The Ear, Neck And Back Of Head?

For over a year I have had sores behind my ear, in the nape of my neck and on the right and left areas of the back of my head. They itch. I ca pick at them and pull off small circular pieces of skin. These small pieces have one or two tiny black dots inside and sometimes, what looks like a tail. After pulling them off, sticky puss exudes from the spot. I used head lice shampoo to no avail. I switched shampoos to no avail. I don t have dry scalp or dandruff.