The actress, who's in the new Starsky and Hutch film, went from a 32B to 36DD after plastic surgery.
But she admits she sometimes wishes she had never had the op, reports The Sun.
Carmen said: "I do regret it sometimes, I think I was fine the way I was. I had nice boobs before - they were small, but nice.
"But I met this girl who'd just had hers done and she kept saying: 'You'd look really good with them too.' Of course, I could have them undone and reduced."
However, she said that would not go down well with husband Dave Navarro, of rock group Jane's Addiction.
"Dave's like: 'Go bigger!' And I said: 'No way, they're big enough!'"