Welcome to Healthcare Magic forum.
Considering the information you have provided it does seem that your son has had a blunt injury
to the head or face resulting from the fall.Even head injuries can cause swelling of the eyelids apart from local orbit injuries.
Minor bruises do resolve on their own within a week which is most probably the case with your son assuming that he has no external bleeding, no vomiting, dizziness
, pain and minimal swelling.
If he has any difficulty in vision, fever, worsening swelling or pain, any vomiting, dizziness or seizures then you should seek prompt consultation as it may signify an underlying serious injury.
As of now it doesn't seem an emergency and a routine appointment with an ophthalmologist or his pediatrician
would be advisable just to rule out any internal injury to the orbit of eye or skull.
The bruise itself may cause some discomfort due to pain and swelling which can be decreased by prescription strength analgesics like acetaminophen
as per his doctors advise.
So please do not worry and do keep a watch on the progression of his symptoms.
Hope this information is helpful to you.
Wishing him a speedy recovery.