"I thought that first night that I came out of the hospital, I was gonna die out of pain," she said. "I didn't think I could physically endure that much pain. I mean, I looked like I was hit by a truck. My body went through so much trauma ... little precision cuts, you know, throughout my entire body."
Montag described an ugly recovery period, during which the simplest of tasks were virtually impossible.
"I couldn't even go to the bathroom," she said. "I couldn't even walk for days. My face was so swollen. You know, my ear, everything had stitches on it. My back was black and blue.
"No one should look like that," she said. "You should only look like that if an accident happened and you're fighting to survive."
Not expecting to be in such horrible pain, or to look like she had been "hit by a truck," Montag said she was shocked at the toll the procedures had taken on her body. She claimed Ryan had made it all sound easy and didn't properly inform her of the painful outcome.
"I do not feel like I was prepared enough for this," she said. "Maybe I should have known. But how can you know when your doctor's saying, 'It's just a little of this, it's just a little of that'? You know, it really becomes a lot."
"I definitely think I should have been way more informed," she added. "I think that doctors should really walk you through all aspects of it, not just the glamorous side of it. Doctors, it's like they're selling you cookies or something."
Ryan died at age 50 earlier this year in a one-car accident when he drove off the Pacific Coast Highway in Los Angeles, reportedly after posting a tweet while driving.
Montag said that among the things that he failed to warn her about was that getting her ears pinned back would be an agonizing procedure.
"If I would have known that, I would have never done that," she said. "They pretty much cut your ear off and re-sew it on. ... They cut the whole back off and then re-pin it, and then they cut off some of my earlobe."
The difficult recovery also put a strain on Montag's new marriage to husband and "Hills" co-star, Spencer Pratt.
"He didn't sign up to be the nurse to his 23-year-old wife at the time, day and night," she said, describing how she was obsessed with how her healing was going and how she would constantly ask him if she looked okay.
"It was so traumatizing what my body looked like. I couldn't look in the mirror. I was hysterically crying ... and he's like, 'I didn't marry this girl.'"
The couple filed for divorce in July 2009 after just 15 months of marriage, although the divorce case was withdrawn in October. The two reportedly renewed their vows at a small ceremony in California last week.
Pratt wasn't the only person in Montag's life to struggle with her transformed self. In the sixth and final season of "The Hills," Montag revealed her new face and new body to her shocked mother, Darlene Egelhoff, as the cameras rolled.
"I'm sorry, it's very weird and very awkward...It sounds to me like you want to look like Barbie," Egelhoff told her daughter during the show's taping. Montag quickly replied that she did want to look like Barbie.
Montag told ABC News that off-camera, her mother apologized and said she wouldn't have reacted the way she had if they weren't being filmed, which made Montag so furious, she said she still isn't speaking to her mother.