CO2 Laser - couldn’t see a difference

I had three fairly aggressive treatments and have nothing to show for them (minus a few thousand missing in my account). I don’t know if my skin is just difficult or what. I don’t blame the nurse who did the treatment at all—she is very knowledgeable and wonderful. But we closely scrutinized my before and afters and even she admitted she couldn’t see a difference. My treatments were a few months apart, and yes, we waited until after the full effect should’ve taken place. I have a fine line on my forehead that didn’t soften whatsoever, texture that didn’t smooth out, and mild laxity that didn’t tighten up. I’ve had zero luck with CO2, ultherapy, or Halo, so perhaps my skin is just more difficult than most.