Could a sneeze pop my suture? (Photo)

It is unlikely that you have caused any suture damage from sneezing and it sounds like the bulge is due to a fluid accumulation. A seroma (or fluid collection) is a common and frustrating problem after a tummy tuck. I recommend being patient and wearing compression garments to help minimize the swelling. Your bulge should resolve when the fluid accumulation resolves. #tummytuck #recovery #seroma 

I think this is almost impossible. Nevertheless, if you have concerns visit your plastic surgeon and let him check the area in question.

Depending on what type of suturing was performed and what pattern it was in, it is possible that the force of a sneeze could pop a stitch. The fact that there is fluid there makes it more likely that it is just a fluid collection and not a popped stitch.