I have a mole on the back of my neck. It isn't painful or anything, but sometimes its gets enlarged and if I squeeze it, thick white stuff comes out of it. This has happened twice now, I have had moles removed in the past and have had them biopsied, and they all have come back benign. I have a few spots that I am to watch to see if they get any bigger. I have fair skin and skin cancer runs in my family. Should I be concerned with the mole that has white stuff in it?