Thank you for the question.
Direct physical examination will allow for accurate diagnosis. Differential diagnosis includes fluid accumulation ( seroma), laxity of the abdominal wall, soft tissue swelling, problems with suture material coming to the surface, infection, fat necrosis etc. Continued follow-up with your plastic surgeon is in your best interest.
Without examining you or seeing before and after pictures, it is difficult to give you specific advice. However, 7 weeks after surgery a great majority of the swelling should be resolved. Any lump or bulge you feel could be a fluid collection, retained fat, palpable stitch or many other possibilities. Hopefully you have discussed your concerns with your surgeon at your post op visit.
I'm sure you've spoken to your surgeon about it, but a bulge can be fluid, swelling or even an area of the fascia (muscle covering) that is less tight than the tissue around it, allowing abdominal contents to push it outward.
A tender bulge around the belly button 7 weeks after TT
By 7 weeks after surgery much of the swelling has dissappeared. While it is possible that this is still swelling, you should discuss this with your surgeon, particularly since you describe this as being tender.
Bulge around belly button after tummy tuck
Hard to say without examining you. A bulge could be a number of things including but not limited to fat, swelling,scar tissue,hematoma , suture, or even a hernia. Your surgeon should be able to tell you by examining you.