I'm A 59 Yr Old Female. For The Last 10

I'm a 59 yr old female. For the last 10 years there has been a dent in my skull that keeps enlarging. It's in the bone. I've recently started developing tiny bumps on the skull but tonight I had like a sunburn pain on top of my head and felt a large lump there. I had hubby look at it and he said he could feel the lump but there is no difference in that area than the rest of my skull. What could be going on?