I haven't had this problem (don't have my belly button pierced), but if it's red and swollen and if there's any discharge or yucky puss-like stuff coming out of it, then it's infected. I would bring it up with your doctor, definitely put some Neosporin or other topical cream. Yes, it may close up, but that's much better than risking a bad infection. If you don't do something about it, I think the infection can get bad and could eventually be harmful to the baby. So, when it comes down to it, the piercing doesn't really matter, your baby does. Just do what you need to do in order to heal it, even if that means having the piercing close up. (but ask your doc, it may not be a bad infection, it may be something you can clear up pretty easily, and save your piercing)