What Causes Vomiting And Stomach Ache After Being Hit On Head?

my 4 yr old son hit his head at the bedframe. after 12 hrs, he complained of stomachache and vomited 5 times thereafter telling me being relieved of stomachache every after vomiting.. his vomitus consisted of ripe mango not digested which he ate 6 hrs before he vomited. i had him ct scanned.there is "probable subacute subdural hematomas". he also had 37.8 temp. now after 2 days of the accident, he is back to normal. should i worry about the CT scan result? is the vomiting related to the hit. tnx. from philippines