Thank you for your query.
I appreciate your description of the event and the problem. In my opinion you need not do anything. The pain should subside and he should be absolutely fine in the next day or two. In case the pain persists you can give him some analgesic
in the form of paracetamol/acetaminophen
6 ml. three times a day. You can provide some hot compresses at the site where it hurts.
I hope I have answered your qurey to your satisfaction. Feel free to revert back in case you require any clarification.
Wishing your son all the best.