Cat banged his head on the edge of a wooden door??

So my cat was walking out of a room.. as he was walking out, he saw my dog walking towards him in the hallway. He quickly turned around and ran back, but on the way back to the room, he hit his head on the edge of the door. Not to pointy side, just the flat side. It made a terrible noise. He did not seem phased though after.. he even played. I touched it and he did not have any reaction. Could he have damage? 

Most likely not. Just take a peek at him make sure he doesn't have any lump or really sensitive spot when you touch the area that was hit. Take a peek at the nose, eyes, and teeth if you can and make sure everything is intact. Watch out for any signs of wobbly walking (drunk) behavior. To get brain bleeding you should have to hit your head harder than just running into a door. You should be just fine!

while it's possible that your cat may have a concussion, i think it's unlikely. cats have both stronger and thicker skulls than humans, and concussions in cats is rare. symptoms to keep an eye out for are lethargy, anisocoria (which includes the symptoms: one pupil of their eyes being more dilated than the other, loss of coordination, blindness, and an increased respiratory rate or abnormal breathing), and seizures. honestly though, your boy more than likely won't experience any of those symptoms. it's things like being hit by a car or falling from great heights that usually cause head trauma in cats.