Small hard lump on head (pic included)

[Baconking]

Any idea what this could be?

I'm prone to cysts on my head but this one is small and hard, doesn't move like a cyst does. It's not squeezable, too hard, so not like a spot... is it worth a GP visit? It's not painful.

Any unexplained lumps should be seen by a doctor, definitely get it looked at!