The Amazing Transformation of Holly Madison.

Holly Madison arrived at the Playboy Mansion in 2001 and become a part of the then larger stable of all blonde girlfriends jockeying for a place in Hef's heart and magazine. She was not a bombshell like the rest of the girls, but there's nothing that a little money can't fix.

It looks like she has had:
1. facial fillers (to make her cheeks and under eye area fuller and younger)
2. lip augmentation
3. rhinoplasty
4. a brow lift

Source