There are actually exercises you can do! I know this is an older post, but I thought I'd just put in my 2 cents in case anyone is interested.

I've learned some exercises from an exercise DVD I had awhile back. I've since lost the DVD but continue to do the exercise. It workes better than any cream and it's easy and doesn't take long. Here you go:

Sit on the edge of a sturdy chair/bench/sofa. Slowly lean your head back as far as it will go - without moving your back or anything - so that you are staring straight up at the ceiling. Next, jut your chin upwards without opening your mouth wide. Feel the skin under your chin - feel how tight it is? Hold for as long as you can. Then release, wait 5 seconds, repeat. Do about 15 reps each day and you will motice tightening in about 2 weeks.

This worked for me! It helps if you have sagging or double chins or if you want to prevent sagging or double chins - which is why I do it. However, if you just have a lot of wrinkles or whatnot, this probably won't help.