Wait until after she sheds & re-assess. Keep the humidity up some to facilitate the shed process, & bear in mind that BPs shed the outer linings of their nostrils too, &
that can be responsible for some noises when they breathe, especially if there is any debris or even some bits of shed that remained there from her previous shed. So,
bottom line, don't panic. Watch to make sure there's no bubbling & excess mucus in her mouth, open-mouth breathing, or any signs that she is really having trouble
when breathing, & in ALL likelihood, "this too shall pass"....after she sheds, that is.

And if she persists in whistling, by all means teach her a good tune... (joking!)