I'm thinking of getting Thermage but am confused as to what is it used for. I've heard it helps tighten skin and improve acne scars, but what is the purpose of getting it under the eyes? Some people have gotten it there, but what are the benefits? I was thinking of that area to increase fullness (as I was told Thermage helps collagen production). Anyone have feedback about this? Also, what is the average cost? Thanks!