My husband has a knot on the top of his scalp. Its a sabaceous cyst. His mother had the same thing and got it cut out. She said it wasn't bad at all. My husband has yet been to the Dr. to get it cut out. He says it doesn't bother him. Its about as big as a huge marble. He's probably had it about 8 yrs. I'd go to the Dr. just in case. Hope everything works out! T.