Daughter's friend group doing something sus on TikTok

So my 14yo daughter mentioned that some girls at school are doing one of those challenges where they film themselves without parental permission and post it. She said it's "just dancing" but ngl I'm worried. I asked to see what she's doing on TikTok and she shut down completely. Now I'm that dad but also... I want to understand what's actually happening vs. assuming the worst. Do I sit down with her and ask to follow her account? Demand her password? I don't want to invade her privacy but also she's 14. Anyone navigate this successfully?