A former patient of retired neurosurgeon Ben Carson called him a "liar" and says she regrets having him operate on her brain tumor when she was just a child in 1995.

"I regret ever having met him, I wish I didn't," Karly Bailey told TheWrap. She says the GOP hopeful botched surgery on her brain tumor and "ruined" her life.

Her father John Bailey said, "I made the worst decision of my life when I agreed to let him operate on my daughter."

Karly says Carson went against her parent's wishes when he operated on her brain tumor. Her parents wanted the retired neurosurgeon to partially remove the tumor because of its proximity to the brain stem.

Yet, he removed the tumor in its entirety where she claims his procedure left her with bad side effects. Now at age 27, she is paralyzed on her right side and she suffers from vertical nystagmus which causes severe dizziness.

After going under Carson's knife, Karly spent seven months in rehab. She looked so disfigured after her recovery that students bullied her.

"She was called a freak because of her face," John said of his daughter's experience. "She had to learn how to write with her left hand."

John claims that Carson also made several "misstatements" of medical facts in his sworn affidavit in order to cover up his medical mistakes.

His daughter says she is shocked that Carson is even using his résumé as a brain surgeon to run for president.

"The general public does not know who Ben Carson is," she said. "I want them to know the kind of person he is. I used to ride horses. I was good at it. After the operation I couldn't even stand up."

Meanwhile, Carson is one of the leading GOP candidates along with another non-politician, Donald Trump. Although Trump is on top in early polling, Carson is treading right behind him while other candidates are receiving single digits in early polling support.