The answer to your question depends on how your plastic surgeon corrected your rectus diastasis (muscle separation). Obviously, the muscle repair is one of the most important pieces of a tummy tuck. If the muscle repair comes apart, you will have a bulge, either above or below the belly button or both.I believe it is most unlikely that your muscle repair would fall apart if your tummy tuck was done by a well trained and experienced Board Certified plastic surgeon. Every plastic surgeon has his or her own technique for muscle repair, so only your plastic surgeon would know the likelihood of their own technique to have their muscle repair unravel secondary to a coughing fit.The process by which all plastic surgeons repair abdominal muscles is more art than science. By that I mean, we all grab a certain amount of fascia covering the rectus muscles and bring one side together with the other. The tensions on these two pieces of fascia on either side is never equal, therefore coughing could lead to a tear in some of the fascia and still keep the muscles together. My personal, hopefully tear proof technique, is first sewing the two sides of the fascia together with a thread as thick as kite string in a figure of 8 fashion to decrease the chance of this layer coming apart no matter what kind of lateral or diagonal movement your abdomen makes. Then I cover this layer with a layer of suture that is strong and, by its nature, unable to pull apart. This is done from the bottom of the sternum to the belly button, and then from the belly button to the pubic area. All the doctor mumbo jumbo above means it is unlikely to pop a single stitch and have your entire muscle repair separate, and very often a popping sound plus pain is unrelated to muscle separation.At this point, take a deep breath, trust your surgeon, and stop worrying.