I had CO2 laser resurfacing years ago. It didn't change the surface of my skin one bit, but it really tightened up the collagen underneath (better than Thermage). When I was in my late 30s, I looked like I was in my early 20s. I would get carded at casinos. The results lasted for years.
The huge downside was that my face scabbed and swelled so badly I looked like a freak. i could not go out in public for weeks. I looked so horrible that when I looked in the mirror I thought I had made a serious mistake and ruined my looks. I couldn't see how the mess that was my face was going to heal up and ever look normal again.
There was one burn/scab that went into my bottom lip. It cracked and I could see into the interior of my lip. I was very careful not to disturb this scab because it would have scarred badly but amazingly it healed up and left no trace.
I highly recommend this for sagging skin who can hide from the world for about six weeks.