If your sons eyes were dilated equally, that is probably fine. If one eye dilates and the other not, it is a more serious concern. It is possible for him to have a concussion (like a bruise on the brain from being bounced against the skull). Most of these resolve on their own without problems but can take a few days.
If he has nausea, vomiting, loss of consciousness, visual disturbances, balance problems, prolonged headache or dizziness you should take him to a doctor or hospital for evaluation. Most children will rebound quickly and act normal so if this is not the case, talk to your pediatrician.
It can be challenging being a parent of an active child. Best wishes.
The answers in online forums are for information only and are not intended to substitute for medical advice and care. Please see your personal health care provider for further evaluation of your individual case.
Debbie Miller, RN