I'm considering surgery because I have a small chin,
 but I'm worried that it might cause sagging like a double
 chin.
I have a lot of fat on my face, my elasticity isn't good, and I'm in my late 20s, so
 I think it's a good condition for sagging.
 
I wrote that the sagging is severe because they're removing bones that don't have cheekbones or squares. Is this also true for front chin advancement?
 First of all, since the bone is cut, will there be sagging even if it advances?