Goose egg bump on babies head

 My eight month old son was sitting next to the wall and lean forward just into the wall in the right spot, where it gave him a little goose egg bump in the middle of his forehead that swelled up right away and is blue and red. It looks bad, but he’s not upset or anything. He won’t let me put ice on it. Is there anything else I can do? He definitely seems fine not in pain but it does look bad. I know that can happen to babies. What can I do other than ice since he won’t let me put ice on it?