Thank you for your query.
In view of a similar history in the past you have done the right thing by seeking medical help
. I would disagree on the issue of hives
as they do not leave bruise
like spots in the area where they appear. It is advisable to keep the child under observation and re-visit the doctor if any further developments take place.
I hope I have answered your query to your satisfaction. Do revert back if any clarification is required.
Wishing your son all the best.