Tik Tok in primary schools

[bombaychef]

My DD age 10 has very very restricted access to Tik Tok which I have only allowed as most of the girls she's friendly with in her class have it. I have full access and check everything she posts. She only has 10 followers / friends on there.
Some of the girls however (and boys for that matter) have un secured accounts and 300/400 followers: not her immediate friends but children she knows and can see the accounts off. Parents must not be checking as surely this makes them very vulnerable?
There's a lot of really bad language and references to guns / sex / violence / b*tches etc. Some of the kids are only 8 or 9 and the oldest I've been looking at are in Year 6.
Anyone else encountered similar? I'm torn about speaking to school about it but feels like a safeguarding issue that children need to understand

@Juliette20 I assume her account is private and not open for all the world to see?

Thanks all. I ended up going into school to chat to HT about all the related issues. I also spoke in passing to lots of parents. The vast majority either didn't know what TT was or thought their child didn't have it. (Incorrect). School are now implementing stricter controls after more incidents this week.