How would I know if I've popped pulled a suture/stitch? (Photo)

Hi there, Clairecluck, and congratulations on
your recent tummy tuck. The good news is that, at 10 weeks post-op, it's
unlikely that you've experienced a suture "popping" or breaking. Even
if you did, your incision should be healed enough to minimize the risk of it
reopening. Instead, the sensation you experienced could be the result of shifting
or tearing scar tissue, which is not a medically urgent event. Keep an eye on
it, particularly for pain, warmth, or excessive redness. If the condition of
your navel seems stable, it's perfectly fine to wait until your next follow-up
appointment to consult with your surgeon. You can also call the practice if you
are still concerned. Good luck!

It is entirely possible that you popped something if you felt it and there is a new bruise.  It may have been just breaking up of scar tissue.  It will likely have little significance.

 It looks as though a buried suture has worked its way through the skin. This in no way compromises the integrity of the repair but will require some minor wound care.

As a general rule: at about 6 weeks sutures loose 50% of their strength, because the body ( at 6 weeks) has maximised the scar production. So, there is a very good possibility this was scar that was pulled or slightly torn. It should n't be a problem, but to be certain have your operating plastic surgeon evaluate you.Good LuckStephen M. Davis, MD, FACSGreen Hills Plastic Surgery