I had it used a few years back, and it worked, but the results were not "spectacular." My PWS is on my forehead, from my hairline to my upper eye lid. He only lasered from my eyebrow up.
I also swelled up fairly bad with it (this may also be due to the local anaesthesia my Dr injected, tho)--it was not unusual for my eye to swell shut.
My birthmark did lighten, and the cobble stone look went away, along w/ the thickening I was starting to experience, however after about a year (roughly 5? 6?) treatments, there wasn't any more he could do. Roughly 3 years later and I am looking into more treatments, but looking into a different laser that may be more effective for me.
I also did not like him very much.
I would probably try to see if there is someone else in the area who uses a different laser, as well as ask him about swellings post-lasering. And see if he has pictures of any previous PWS lasering he has done.
The hope a dream and the wings to be free