Liposuction 7 months ago. Now all of a sudden my stomach is saggy and has a few dimples. Why would this happen?

Most likely the reason is because you was candidate for a TUMMY Tuck even before the liposuction.The truth is there is no procedure which tighten the skin once it is flaccid in a moderate-severe degree.The removal of the volume will only make the skin saggier. Be encouraged. Everything is fixable and at the end will be loving your beautiful body.Dr. Cardenas

You are now about 6 months out from your surgery, and this is when the swelling usually completely subsides. The combination of this and perhaps some weight loss may have accentuated the laxity.  Best to see your surgeon.  Good luck.

While it would be helpful to see photos before and now, I imagine that the areas of suction are now somewhat "deflated". The ultimate result of suction lipectomy depends upon your skin elasticity and now that all of the swelling is gone, the skin has relaxed and has not shrunken as much as you had hoped. 4000 cc's is an aggressive suction. In June and July, while your skin was still a bit swollen (It often takes a good 3-4 months for the swelling to resolve) the thickness of your swelling kept you skin looking good. If you do have extra skin now, wait until 6 months post-op and then you'll have a better idea just how much extra skin you have. There are some non-invasive skin treatments that may help (for example, Ulthera or Venus Legacy Radio Frequency) but it is likely that the definitive procedure to correct your skin laxity will be some form of an abdominoplasty where the extra skin is removed surgically. Good luck, I hope you ultimately get the result you seek.