Circumcision Question/Problem

My son was circumcised in the hospital one day after being born. We cared for it and it healed, however after it healed we noticed that the skin was coming up over the head of his penis again. I asked the pediatrician about it and he said that sometimes happens if they “leave a little extra skin” but that we should just pull it back each time we change his diaper so it doesn’t stick and he will grow out of it by adolescence. I’m just a little concerned this isn’t going to happen. Sometimes it’s so sunken in that he doesn’t even look circumcised. I don’t want him to have an issue later in life or risk him being bullied because it doesn’t look right. Has anyone else had this issue? Did it fix itself or did you have it redone?