I have a bump on my shin from about 4 weeks ago what is it?

It happened while I was kickboxing. It doesn't hurt much but If you press on it hard or knock on it it does hurt a little bit. Its fairly hard and is about a 1/4 of an inch big. Is this anything I should worry about or do something to fix. I know if I get kicked there again or block a kick in that spot the pain would come back. Anyone have anything like this?