The reality is, it's never going to be flat and firm without surgery. You can tone it
some, but the skin has been stretched out for a period of time, and it wasn't being toned while shrinking (which also wouldn't completely fix the problem). Nothing short of surgery will completely repair it. But, if it's like what I deal with, you can tone it up enough to where it won't be as noticeable, plus, it's low...not like you're going to be showing that area off frequently.
Just don't bend over and look in the mirror like I would do and get myself discouraged. LOL One day, my rich uncle might get out of the poorhouse, and I might spring for a tummy tuck. Dunno.