When Will I See Skin Retraction After Vaser Lipo?

Unfortunately it a is a waiting game and you need to be patient.  Everyone's recovery period differs.
Are you engaging in cardio exercise again?
Remember that this is a two way process.  The lipo takes care of removing excess tissue, but you also need to keep in shape and watch your diet.
Skin retraction can take up to 6-12 months.

Many studies indicate that there is less injury to the body with Vaser than with traditional #liposuction. Recovery from Vaser Liposuction is based on the level of soreness and bruising experienced by the patient. But, it can vary among patients. As with traditional liposuction, there are no large incisions  or effect on the muscle and other underlying tissue. Therefore, #healing time may be less than anticipated by most. Therefore, Vaser patients may experience less #pain or discomfort, #swelling (#edema) and bruising post procedure due to the nature of the technique.  
Swelling is not uncommon. Gentle #walking may increase circulation and help to alleviate swelling. But you must not strain or push yourself. Also, if you were provided a post-procedure #garment, be sure you are wearing it until prescribed otherwise by your doctor. The purpose of the post-procedure #garment is to provide some gentle #support and to reduce swelling. If it feels too tight or causes pain, take it off. Many patients wear the #elastic garment for several weeks after procedures, as directed by their doctor; some choose to wear it longer for several months for comfort.
The final results of the procedure are typically most noticeable 2-4 months following the #Vaser. So, you must have patience. The swelling will gradually diminish while the contours of the treated area(s) can continue to improve up to one year post procedure; becoming more apparent in appearance. If you have concerns about your healing, or pain that you question to be unusual, it is important to call your plastic surgeon to discuss these further asked to be examined. 

Since you just had surgery in Mid-March, you have to be patient with the results. I usually see the majority of the swelling dissipate in about 6-8 weeks. However, exercise and activity level, as well as individual healing rates may all impact the results. By Mid-May ( 2 months after your surgery) it probably will look good. But, in general, Vaser lipo results take 3-6 months if not longer to see the "final" results.