"'And I didn't realise that, 'Oh s**t, I'm actually looking really strange with injections and doing stuff to my face that I would never do now'."
Cox added she realised people were talking about the work she'd had done, which triggered her to realise she needed to "stop".
"I'd say, the day you realise what your friends were talking about. Because people would talk about me, I think.
"But there was a period where I went, 'I've got to stop. That's just crazy.'"
The Cougar Town star, who lives in Malibu, California, said media scrutiny played a role in her desire to dabble in cosmetic touch-ups.
"The scrutiny is intense, but I don't know if it could be more intense than what I put on myself," she added.
"(But) I'm a (beauty) product wh*re. I will try anything."
Cox, who is worth an astonishing $210 million, is currently promoting her new TV comedy horror series, Shining Vale, after her surprise appearance at the Brit awards this month with her Snow Patrol boyfriend, Johnny McDaid.