Severe skin damage and wrinkles after IPL?

I m 26, caucasian, with flat brown and red acne scars. I was reading into IPL treatments, but have come across many people who have had the treatments at even reputable places and have had their skin damaged in a way that cannot be fixed. A typical example with photos and links in her subsequent posts: What causes this to happen? Why isn't this ever mentioned by doctors when discussing the risks?