Swelling after a tummy tuck is normal. It takes 6-8 weeks to have the swelling resolve. Swelling can improve faster for patients who are more compliant with compression garments and are a little less active. So don't worry, swelling is a normal process of healing after any surgery. Continue with your compression garments as recommended by your PS. I'm sure you'll love your results once you are all healed up.
Web reference: http://www.basuplasticsurgery.com