"I have flat feet and somewhere in the 25 years of my life, I tore the cartilage in my bunion in both feet," she toldOK! Weekly after Monday night's performance episode, adding she was advised to undergo an operation.
"I said no. I didn't want to have it because I believe if you start cutting things, you have a whole new set of problems and it wasn't that bad, so I deal with it."
However competing on Dancing with the Stars' ninth season as a celebrity participant apparently hasn't helped the injury and has instead caused more pain.
"Basically, my doctor said, 'Told you so, told you so. You wouldn't be [feeling] this if you had had the surgery.' So I'm going to have to have it after the show," she told OK!.
Osbourne addressed her injury following her final routine with professional partner Louis van Amstel during Monday night's live semifinals performance episode.
"I am on top of the world considering this morning I couldn't even walk," she said during the broadcast. "I had to have injections in my feet in order to dance tonight so it's just been over the moon."
While she subsequently told OK! "it's really not that big of a deal," it was enough of a concern for Osbourne that she tried her best to conceal it so it wouldn't impact viewer voting.
"I didn't want a sympathy vote and I didn't want to get [voted] through because somebody felt sorry that my foot gave up on me," she explained to OK!, likening the pain to a tooth cavity.
"You know when you have a cavity in your teeth? It's like that in the bone of your foot and every time you take a step, ooh," she continued.
"Or when you have your hair in a ponytail for a really long time and that feeling like, stop, my head's killing me! It's like that but constantly in your feet, every step you take, every time you breathe in and your body changes its weight a little bit, it just sends a shooting pain. It is so painful."
Van Amstel added the three-inch heels Osbourne wears for dancing "makes it really bad," and she said it's compounded by her being flat footed.
"I roll my feet in and all the pressure is on the bunion of my foot and it's really painful!" she told OK!.