What we were told after a scary incident with my niece, if they hit their head and a bump comes out, all you have to do is keep an eye out for a concussion. If you cannot see or feel a bump, it means the bump went in and could press on their brain-ER NOW.
Signs of a concussion include loss of balance, sick feeling, blurry vision, persistent dizziness, dilated pupils or just one pupil.
A good thing to remember, if you get a cut on the head, elbow-any place where's there's not a lot of fat between skin and bone, it will bleed more. A lot of blood does not necessarily mean a bad injury. Keep calm and assess. If you clean it and the blood does not stop flowing after pressure is applied, a trip to the doctor's office would be in order for more expertise medical car-unless of course you just want to use super glue. (I'm only halfway kidding) Salt is a good blood clotter, too. Stings like heck, but it works. The more you stress, the more the child will stress and make everything worse.