Hello. Thanks for asking from HCM. I can understand your concern. It is good that you have evaluated pupils. No pupillary reaction to light and dilated pupil is a serious sign of head injury. If it is present, you must consult ER as soon as possible. But according to your finding, other pupil is showing some reaction which is good. His behaviour is normal. All these are good signs. Dizziness and headache after head injury may persist for some time, but if they are decreasing and responding to pain killers then serious injury can be ruled out. I am giving you list of alarming signs and you can observe in your child. Consult ER if you find any of these signs and symptoms. : Vomiting : bleed through ear/nose/throat : loss of consciousness : decreasing consciousness : altered behaviour : change in one pupil size, mostly on injury site At home, you should keep his head at higher level than chest, turn head to side in case of vomiting, avoid sedating drugs. Thanks. Hope it will help you. Take care.