The 56-year-old revealed she had experienced a rare cosmetic side effect of the treatment five years ago which actually increased her fat cells.
"I have been left, as the media has described, 'unrecognisable'," she told her 900,000 Instagram followers.
Evangelista explained it was the reason she'd disappeared from the public eye.
The Canadian model went on to say she had undergone "two painful, unsuccessful, corrective surgeries" after the slimming procedure - also known as body contouring - had had the opposite effect.
