My 1 year old son fell down the front porch (3 steps) and hit his head audibly hard on the cement below. He cried for nearly an hour after that and was inconsolable, and developed a rather large bump over/behind his left ear. Once he calmed down he ate his dinner fine, was alert, ran around normally, giggled and babbled like normal.

I am still a little concerned about a possible skull fracture. Are my worries unfounded, or should I see a doctor tomorrow (he's down for the night now)?