Is it possible that cavitation ultrasound could make me look worse?

I am so sorry you did not get the results you were looking for after your procedure. It is hard to say what happened and what the solution is without assessing you personally.Ultrasound lipo techniques are meant to remove the fat in places that are more difficult to remove. I recommend that you meet with another board certified plastic surgeon who can consult with you to see what you can do now to achieve the results you want. It also depends on how long after your surgery it has been. Firmness and swelling can last for a few months afterward, obscuring your results.

How is your abdomen worse?  Is there skin laxity?  Are there contour irregularities?  Are there asymmetries?  How long is it following the procedure.  Ultrasonic liposuction can be effective for fibrous fat reduction.  The benefits of ultrasonic liposuction include easier procedure, smoother (liquefaction of fat), and perhaps skin tightening.  The result can slowly improve over time (6 months or longer).  Any possible secondary procedures should wait until after this time.