Thank you for your question and the photo. Although I would need to see you personally to be certain, it looks to me as if the belly button is alive, but that there is some separation between the belly button itself and the surrounding skin.While I am not your doctor, and you certainly should speak with your plastic surgeon to get advice for managing this, I would say:1) Unless your sister is at least a surgeon, if not a plastic surgeon, just because she is freaking out doesn't mean you should. 2) From the photograph, it looks to me as if the white material you see between the skin edges is protein and exudate, not tissue (dead or otherwise). The belly button itself is pink, and so is not dead.3) I doubt this is primarily a blood supply issue, and most likely reflects the tension from the tightening you had (in other words, a good thing).4) I believe that this is a common occurrence, and most likely will resolve, over time, regardless of how you treat it.5) Hydrogen peroxide may help you clean out some of the exudate. It bubbles due to exposure to an enzyme in your blood, which always makes people feel good about using it but doesn't actually indicate "bacteria being killed" or any other therapeutic effect.6) Neosporin may be helpful on the open areas, but I would avoid putting it on the skin, as it often causes local reactions and pinkness.7) While it never hurts to see your primary care doctor, I would say that my experience is that, unless they routinely do this type of surgery, they likely have not seen this problem, and how it responds to management. In order to be careful and not miss anything, they often seriously overtreat post-surgical problems. I have also seen them freak out unnecessarily. See #1 above.8) It never hurts to get a second opinion, but it should be from someone who has a lot of experience doing this type of surgery. See #1 above. If you are still worried after speaking with your surgeon, they will probably be happy to help you arrange a second opinion with a qualified plastic surgeon.9) None of the above is to say that other problems may not occur, now or in the future. I cannot provide advice for your specific situation. You should contact your surgeon for specific advice.Now, if your plastic surgeon freaks out, you probably do have a reason to worry.Good luck!