If the child is active and playing, taking feeds normally as earlier then no need to worry. As there was no vomiting or dullness or lethargy you need not worry. If anything like that was there it would have shown symptoms by now. As your pediatrician said only if those symptoms are there you should take him to hospital. Otherwise if all activities are like before then don't worry. Long term effects won't be there if there are no symptoms now. Just crying may be due to pain. Use fever medicine only for pain also. Don't worry. Hope your doubts are cleared.
Health Tips
use rails or pillows in beds for children to prevent falling