Hard lump on my dog's head?

[G22]

Well without seeing the lump, it could be anything.

My husky has something that popped up very similar on her ear, it essentially showed up overnight. After researching I self diagnosed it as a histiocytoma (a benign tumor), but still got her to the vet to get it checked. Turns out I was right, but I'd never assume that. I definitely say get it checked out, just to be safe.