Circumcision and color question

Hi ladies, my little guy is almost 2 weeks old. He was circumcised at 2 days old and the "bell" fell off after 5 days. I've noticed recently when I changed his diaper that the tip of his penis is a purple color. Is this normal? He has a doc appointment on Friday and I'll have them look at it, but just didn't know if u ladies could ease my mind till then. He has pleanty if pee diapers and doesn't seem to be in pain. I've never had a boy before so this is all new to me lol