Stretch belly button after Tummy tuck. Any suggestions? (photos)

I understand this outcome must be very distessing for you.  Your best step is to arrange a review with a fully qualified and experienced plastic surgeon as its difficult to assess your suitability and options for surgery until you have had an in-person consultation.  The belly button could be reconstructed and reduced if you were prepared to accept a vertical scar down the middle of your abdomen.  

Your scar has stretched out and what you need to do now is go get a second opinion since your PS does not want to fix this.  You had your surgery well over a year ago and a revision can be done at this time to fix your problem.  Good luck!