Is this normal for a Circumcision?

I’m a first time mom, and my baby boy is 3 weeks old. This past week he had gotten circumcised at his pediatricians office. For some reason they only do it at the hospital if your pediatrician makes routine visits at that hospital and the pediatrician we chose did not. So this week my son got circumcised. It’s been 4 days since the procedure and last night I noticed a red lump/bump at the bottom of the head on his penis. It’s obviously red because it’s still healing, but this lump/bump seems weird to me. I’m not sure if it’s normal or what!!! Please helppp!!! I’m starting to worry🥺😱