My 5 year old son has two, what I think are bug bites on his leg marks on his leg. They are both roughly the size of a quarter or a little smaller and they are red with a small white indented center. They are itchy but he has not had any other symptoms like fever or anything. I have never seen a bite like this before, any idea what it s from? And is there Anything special I need to do treat it? Thank you!