What happens after a head bump must be treated specifically according to the specific situation. Generally, we need to see the strength of the impact and the specific mechanism of the injury, such as just hitting the door frame by itself, simple headache, dizziness, generally no big problem, you need to go home and actively rest and maintain adequate nutrition. The main concern is being hit by a car or being struck with an instrument, which can be relatively dangerous if nausea, vomiting, etc. occur later. If a coma occurs, it is something even more dangerous, and you must go to the hospital in time for the appropriate examination, clear diagnosis and timely treatment.