In a video, Feroza Aziz accused Beijing of “throwing innocent Muslims in concentration camps” as well as kidnapping, raping and murdering them and forcing them to eat pork and drink alcohol.
She described it as “another Holocaust”, claiming people who go into the camps don’t come back alive.
Ms Aziz said the Chinese-owned platform had blocked her from posting for a month.
But on Wednesday TikTok put out a blog post saying there had been “confusion”.
It said she had actually been blocked for a previous video on another account that had included an image of Osama bin Laden – but acknowledged it may have been satire.
TikTok said the Uighur video was posted to Ms Aziz’s second account, but that a “scheduled platform-wide enforcement” had blocked her device and stopped her accessing both accounts because of the bin Laden image.
It said “human moderation error” also caused the video to be taken down for less than an hour on Wednesday.
“It’s important to clarify that nothing in our Community Guidelines precludes content such as this video, and it should not have been removed,” said the post by TikTok’s head of safety, Eric Han.
“We would like to apologize to the user for the error on our part this morning,” added Mr Han.
“In addition, we are reaching out to the user directly to inform her that we’ve decided to override the device ban in this case.”
Ms Aziz’s clip, which was also posted on Twitter as well as TikTok, was disguised as a make-up tutorial which started with her reaching for a pair of eyelash curlers.
But she quickly started talking about the Uighurs and what she wanted her followers to learn about the alleged mass oppression of them in China.
She began the 40-second clip by saying: “Hi guys I’m going to teach you guys how to get long lashes, so the first thing you need to do is grab your lash curler, curl your lashes obviously.”
But she continued: “Then you’re gonna put them down and use your phone that you’re using right now to search up what’s happening in China, how they’re getting concentration camps, throwing innocent Muslims in there, separating their families from each other, kidnapping them, raping them, forcing them to eat pork, forcing them to drink, forcing them to convert to different religions, if not, or else they’re gonna of course get murdered.”
Aziz wrote on Twitter on Monday she had been blocked from posting on TikTok for a month, but added: “This won’t silence me.”
Earlier this week, leaked documents about Chinese detention camps dramatically contradicted government claims they are voluntary job training centres.
Classified documents appear to confirm the testimony of many former detainees that they are centres for forced ideological and behavioural re-education.
More than a million people from ethnic minority groups, most Uighur Muslims, are in the camps in the far western Xinjiang region.
China’s embassy in the UK has dismissed the leak as a “fabrication and fake news”.