What to do if I banged my head, really hard?

Possible concussion. sxs: + or – loss of consciousness, headache / pressure, can't recall event, dizziness, v coordination, ringing in ears, confusion, slurred speech, nausea / vomiting & fatigue. For concussion seek medical care. Seek urgent treatment for loss of consciousness, on-going confusion, seizures, unequal pupils, recurrent vomiting, change in level of consciousness, loss of balance or difficulty walking.