I'm curious to know if anyone else's child has a reaction at the injection site. It seems like my son reacts to something, not sure what, at his injection site. Its quite clear where the injection was made because there is a red circle around it, about the size of a dime. I don't quite know how long it takes to appear, but it is there when I go to give him his next injection, about 12 hrs later, but then disappears by the following injection, 24 hrs later. He doesn't complain about it being sore or itchy. I don't get these marks at all. I wonder if its an allergy perhaps or something else.