Dr. Ben Carson’s campaign spent days playing defense after a CNBC moderator challenged the candidate on his ties to a supplement company during the last Republican presidential debate.

But after a very bad week that saw various news outlets poke holes in his powerful personal narrative and call him out for easily disprovable claims about the Egyptian pyramids and America’s Founding Fathers, this week’s debate on Fox Business Network may prove to be an even tougher contest for the retired neurosurgeon.

Carson’s camp was quite busy last week explaining everything from discrepancies in the candidate’s biography to the rationale behind an ad aimed at black voters that featured a Carson-themed rap song.

Here’s a look at the challenges he faces as he goes into Tuesday’s debate:

“Joseph built the pyramids to store grain”

Carson’s bad week started with BuzzFeed’s resurfacing of a very strange theory he floated about the Egyptian pyramids during a 1998 commencement address.

“My own personal theory is that Joseph built the pyramids to store grain,” Carson said at Andrews University, a school with ties to the Seventh-day Adventist faith. He went on to dismiss archaeologists’ consensus that the pyramids house the tombs of ancient pharaohs.

The retired neurosurgeon was roundly mocked for those remarks but stood by them in an interview Wednesday with CBS News. He later welcomed “secular progressives” to ridicule his faith-based theory on the pyramids.

We’ll find out Tuesday whether presidential rival and real estate mogul Donald Trump, who has vowed to use the alternative pyramids theory against Carson, will bring up those remarks on the debate stage.

The Carson rap ad

Carson’s campaign on Wednesday announced a $150,000 radio ad buy aimed at urban black voters. The ad featured a rapper named Aspiring Mogul urging listeners to “Vote! Vote!” over clips of Carson talking about personal responsibility and freedom. The retired neurosurgeon later said the ad was his campaign staff’s idea and he would have opted for a “little different approach.”

The founding fathers “had no elected office experience”

The Wall Street Journal on Thursday spotted a historical inaccuracy in one of Carson’s Facebook posts. Carson often replies to fans’ questions on the social media platform and bungled a fact about the Founding Fathers while addressing his lack of political experience.

“Every signer of the Declaration of Independence had no elected office experience…What they had was a deep belief that freedom is a gift from God,” Carson wrote.

After the Journal pointed out that several of the nation’s founders were elected to colonial assemblies, Carson’s campaign said the post was edited to clarify they had no experience in “federal” office.

Changing details about his violent outbursts as a child

On the campaign trail, in his books and in past speeches, Carson has touted his personal narrative of overcoming anger issues as a youth to become one of the most renowned surgeons and respected public figures in the country. Carson’s story of attempting to stab a friend named “Bob” in the ninth grade—soon after which he says he had the religious experience that set him straight—is the seminal moment in that narrative.

But a CNN story published Thursday cast doubt on Carson’s telling of his formative years, as nine people who attended school with him or grew up with him told the network that they had no knowledge of any violent outbursts like Carson had described. Carson and his camp dismissed the CNN story, arguing that reporters spoke with people who only knew him after he had a religious experience that dissolved his anger issues. They also repeatedly declined to provide further details about the incidents of violence.

The retired neurosurgeon eventually copped to changing some of the details in the stabbing story and tales of his other acts of youthful violence, particularly altering names to protect people’s identities. He also divulged that “Bob,” the victim of the attempted stabbing, was actually a close relative.

Claiming a “full scholarship” offer from West Point

Scrutiny of Carson’s biography reached its peak Friday with a scoop from Politico casting doubt on his claim of having been offered a “full scholarship” to West Point by none other than the late Gen. William Westmoreland.

Politico’s original story said that the Carson campaign admitted that he fabricated his “application and acceptance” to the U.S. military academy. After increasingly vehement pushback from Carson’s camp and on social media, the publication revised the story to say that the retired neurosurgeon attempted to recast his previous claims of a “full scholarship” offer. The school covers the costs of its students and is effectively tuition-free.

The initial response to Politico’s story, including from many conservative commentators, was that the revelation was damaging to Carson’s campaign. That response was tempered after Politico revised its story, eventually adding a lengthy editor’s note stating that it stood by its reporting. Some of the commentators who said the West Point debacle was a bombshell for the campaign promptly reversed course and blasted Politico’s reporting as a hit job.

A no good, very bad weekend

Politico’s revisions didn’t put a stop to questions about Carson’s background. Carson, who is normally soft-spoken, got testy with reporters when they asked more questions about the West Point offer in a Friday evening press conference. He was also pressed to account for the discrepancies in his biography on the Sunday show circuit.

Topping it all off, The Wall Street Journal unearthed more episodes from Carson’s past that could not be confirmed. Carson’s former high school classmates and biology teacher told the newspaper they couldn’t remember hearing about the retired neurosurgeon hiding white students in the biology lab during a riot. The Journal also found no record in the Yale Daily News of Carson having his picture taken after he passed a psychology professor’s “honesty” test, as he wrote in his book “Gifted Hands.”

Will Carson’s polls fall?

It’s important to remember that before this string of bad press, Carson was riding high in the polls and even surpassed longtime frontrunner Trump in several surveys. Trump himself is a reminder that making outlandish or even offensive statements—think his trashing of Sen. John McCain’s (R-AZ) military record or his disparaging comments about Mexican immigrants—may have little to no impact on poll performance.

Still, there’s no guarantee that the Fox Business debate moderators will steer clear of the Carson campaign’s recent missteps on Tuesday night. While a group of representatives for the GOP candidates led by the Carson camp drew up a list of debate demands that stipulated moderators may not ask “gotcha” questions, many campaigns ultimately declined to sign onto the effort. The moderators have also made clear that they won’t go easy on the candidates.

“We’re here to facilitate, we’re not looking to please the candidates and give them their own produced show, in any way,” moderator Maria Bartiromo told the International Business Times in an interview last week.