What you weigh is essentially determined by two variables: what you eat and what you burn off.
To better understand this, think about the analogy of a bathtub. Water comes into the tub through the faucet and is drained by the drain. The water level to which the tub fills (what you weigh) is determined by how fast water comes into the tub (what you eat) and how fast the tub is drained (what you burn off). At some water level (how much you weigh), these two variables, provided they are constant, will be in what is called equilibrium and the water level (what you weigh) will be constant. Now, suppose you come along and scoop out a bucket of water. The water level will drop. However, eventually the water level will return to the equilibrium level.
A similar thing happens with liposuction. However, for liposuction, it is more complicated because the body swells, following the procedure due to surgical trauma, so fat is replaced by fluid. An equal volume of the fluid weighs more than an equal volume of fat. So while the swelling slowing resolves over a period of months, your body is busy regaining lost fat.
Liposuction is effective at sculpting because the regained fat is more evenly distributed over the body, and not just to the problem area that was liposuctioned. However, it is not expected that your weight will change, unless you change what you eat or how much you metabolize by increasing your work out.
This is why you will hear responsible liposuction surgeons say over and over again that liposuction is not a weight loss method.