"What you just did to Paul Ryan is unforgivable," the voter said. "Why don't you get out before you make a bigger fool of yourself?"
Along with his words on the Medicare plan, Gingrich also told "Meet the Press" that he supported a "variation" on the individual health insurance mandate.
"I've said consistently, we ought to have some requirement that you either have health insurance or you post a bond or in some way you indicate you're going to be held accountable," Gingrich said.
The Gingrich team tried to "walk back" back those comments Monday by releasing a YouTube video of Gingrich rejecting the individual mandate.
"I am for the repeal of 'Obamacare,' and I am against any effort to impose a federal mandate on anyone, because it is fundamentally wrong and I believe unconstitutional," Gingrich said.
In Mason City, Iowa, today, Gingrich became the first presidential candidate to sign the "Obamacare Repeal Pledge," which vows that if elected president, he would sign all bills aiming to repeal the health care law that passed in March 2010.
In a meeting with the Wall Street Journal's editorial board Monday, Gingrich admitted he may have used "too strong language" when criticizing the Ryan plan, but said he thought it "would be politically catastrophic to pass the bill in its current form."
A Wall Street Journal editorial said the episode showed Gingrich's "odd combination of partisan, divisive rhetoric and poll-driven policy timidity," and underscored his "weakness as a candidate."
"This is very very damaging for him," Matt Lewis, a reporter with the Daily Caller, said on ABC News' TopLine. "Despite the fact that he helped lead the Republican revolution and has done a lot of great things over the years, conservatives were already a bit skeptical of him."
Gingrich has run into some trouble by flip-flopping on other issues. In early March, Gingrich said he supported U.S. intervention in Libya, saying the U.S. should "exercise a no fly zone in Libya.
"All we have to say is that we think slaughtering your own citizens is unacceptable and we're intervening," Gingrich told Fox News. "This is a moment to get rid of him, get it over with."
Later that month, he backtracked and said the U.S. should not have intervened.
"There are a lot of other ways to affect Gadhafi," Gingrich told the "Today" show. "I think there's a lot of allies in the region that we could have worked with."
On "Meet the Press" Sunday, Gingrich acknowledged his penchant for making comments that often land him in trouble.
"One of my great weaknesses is that part of me is a teacher-analyst and part of me is a political leader, and one of the most painful lessons I've had to learn, and I haven't fully learned it, obviously, is that if you seek to be the president of the United States, you are never an analyst."