Hi I am Dr.kadhir, a pediatrician
Strep throat can be associated with a condition called
scarlet fever it usually presents with rash( red bumps) and other symptoms are
sore throat, fever > 101°F and enlarged glands in the neck. But the rash appears during the fever and settles down after 4 to 5 days of fever. It never appears after the fever or sore throat settles.
Other possibility is
drug induced rash , but as you have mentioned he is not on any drugs now.
so i can assure you that this rash is neither due to the strep throat nor due to drugs.
It could be a part of new infection either viral or bacterial or an
insect bite allergy. The best treatment could be treating the symptoms. It is important that you meet your pediatrician so that he can look at the rash and decide on the treatment.
Thank you for your consultation in health care magic .