Can fat come back after SculpSure or CoolSculpting?

That is interesting, I was always taught exactly the opposite. You have only so many fat cells after puberty and do not make more. Your existing fat cells can get bigger or smaller depending on caloric intake. Destructive methods such as lipo, and Sculpsure remove those cells. They are gone and not replaced by any new fat cells. If you eat too much the remaining cells will get bigger and if you really eat too much you might look fat again.
What we both seem to look at the same way is that the results are only permanent if you maintain healthy eating habits.

SculpSure and CoolSculpting treatments do destroy some of the existing fat cells in the treated area. Once destroyed, these fat cells do not come back. If a person is treated with one of these procedures and then gains weight, the existing fat cells in the treated area can expand. So in general, the results from SculpSure and CoolSculpting will be maintained if a stable body weight is maintained. If a significant amount of weight is gained, treated areas can still expand.

Body sculpting works by apoptosis, liposuction by removal of the cells. In both cases the body cannot regenerate new fat cells. However, if there is weight gain due to excessive calories, the body will find a place to store the fat. That may mean you will gain fat in other areas or that the remaining fat cells in the area treated could expand. To prevent this, it is best to be at a stable weight for a few months before treatment.