Tummy tuck navel revision (Photo)

I had a tummy tuck about 7 months ago and there is a problem with my navel. I keep getting green clear discharge so the doctor gave me antibiotics but it never cleared. As i have had this procedure done abroad i need to find a doctor local in London otherwise have to fly back out. My surgeon reckons it could be a stitch inside which needs a navel revision. He reckons i may have a granuloma from the stitch. Doctor also took swab and came back clear so no infection. What can this be ?