It is a very common event after liposuction in general, and especially if a machine was used (Untrasound or LASER). Factors that usually lead to it are basically: the amount of fluids used in the surgery, the amount of removed fat, the position during the surgery, your body's ability to handle the surgery (not a matter if it can or cannot but rather "how" it handles it), the type of your skin, any chronic conditions that you might have, the medication used on surgery and the ones prescribed for you after. The swelling usually significantly drops down in 10-15 days, and soon after all goes back to normal. Some addition treatments might be used to speed things up but keep in touch with your surgeon and don't try anything yourself without getting his approval. I'm sure he did a great job with the surgery, and the swelling is not caused by any fault from his side, so keep your trust in him solid and update him. Best of luck!