ET caught up with the former Olympic gymnast and her pro partner, Sasha Farber, following their Mulan-themed contemporary routine on Monday's Dancing With the Stars, where #TeamStickIt revealed the 50-year-old athlete suffered yet another injury just one day before Disney Night.
"[She] popped a rib yesterday," Sasha told ET's Katie Krause. "We just put a Band-Aid over it. She's crazy! I mean, nothing can keep this girl down."
"It's true. We just wrapped it up, real tight," added Mary Lou. "That's why I'm not walking around in a Cinderella dress. She's my favorite princess, but I'm a warrior and that's what Mulan was."
A warrior indeed! Like Mulan, who Mary Lou channeled Monday night while dancing to "Reflection," she says never giving up is something she's done her entire life.
"I'm a little beat up, but I'm OK," she said. "I have to deal with a lot of pain in my life. It is what it is. But it's OK because it makes me stronger."
In addition to her rib, Mary Lou (who was born with hip dysplasia) has also been experiencing pain in her knee. She first injured it and had to have arthroscopic surgery just six weeks before she became the first-ever American woman to win the all-around gold medal in women's gymnastics at the 1984 Summer Olympics.
"It's getting a little worse but we had some medicine," Mary Lou revealed to ET last week following Trio Night. "Nothing's gonna stop me. I had some psychical therapy and taped it up and I'm good to go."
Luckily, Sasha has been a tremendous help in keeping Mary Lou's spirits up throughout the competition.
"Sometimes she's a little hard on herself," Sasha admitted. "I have to remind her every week. But I'm so proud of her. She's just an inspiration to me so much, every day."
Dancing With the Stars airs Mondays at 8 p.m. ET/PT on ABC. In the meantime, hear how another dance duo -- DeMarcus Ware and Lindsay Arnold -- are dealing with the former NFL star's broken finger.