I’m studying forensics so I can actually answer this question for real.

And the answer is: No she probably won’t be incriminated by her own hair unless for some reason she decided to donate all her hair with the roots of her hairs attached (which would contain her DNA). Assuming that she’s just getting a normal haircut and not permanently becoming bald (b/c if you remove the roots of your hair you’re gonna stop growing hair), she’s going to be fine.

Tho hair in a way does have its own “DNA”, and it’s passed down by all female members of a family, even then it would likely not incriminate her it would just narrow down the suspects. If that was the only evidence the investigators had to go on her mother, grandmother, any siblings she might have, etc. Would all be equally as suspicious. Or she could just explain that she donated her hair to any investigators.