What Do Small Indentions On Skull Indicate?

My husband has two small indentions on the top of his skull. One he used to pick at and it got deeper, the other he doesn t know where it came from. They are not painful in any way. He has fair skin so they are kind of pink but not red or angry looking. He has had one for a couple years and the other we re not sure. He is 48 and in excellent health. Should he get it checked out?