Outside of plastic surgery, is there anything you've found that helps with loose or sagging skin? The skin under my chin looks terrible, and I'm wondering if there's anything I can do to make it more firm. I'm 42, so I realize that there may not be a whole lot. ;)
Skin does shrink very slowly after massive weight loss for up to 2 years. So what you have today will change. And change again and again. You are still very new and there is no way for you to know where you will end up.
Exercise will develop the muscles under the skin but skin itself has no muscle fibers that can be tightened up by exercise. It's good to keep your skin hydrated but again there is no magic potion.
2 years or so after you are done losing you can look in the mirror and be pretty sure you are looking at the finished product. Then you can evaluate and decide if and what you want to change.
Start saving now.
Only plastics but if it's any consolation, the area under your chin eventually sags for everyone, so plastics or loose skin under the chin is in everyone's destiny.