How long should I wait after completing the HCG diet to get liposuction?

You need to lose weight first before undergoing any cosmetic procedure to get the best outcome. Liposuction is not a weight loss procedure, rather it is for sculpting and defining and removing problem areas that cannot be removed with weight loss and diet / exercise alone. For best results, it is recommended to be at your ideal or stable weight before getting a sculpting liposuction procedure.  With skin laxity, a tummy tuck or lifting procedure could be performed at the same time. I recommend getting a formal evaluation with a bariatric doctor or dietitian. Best, Dr. Emer

In all honesty, liposuction should really be done mostly for problem areas.  If, for example, you are generally well proportioned but have one or two areas that need some sculpting such as your inner thighs or "love handles", then lipo will provide you the best results.
We have even treated clients who have been Olympic athletes but who still had stubborn areas of fat that did not respond to aggressive exercise.  This also suggests that liposuction is best suited for this purpose, rather than as a weight-loss procedure.  In fact, I tell clients that any weight loss they may see will likely be subtle.
Hope that  helps