This is a recognized condition. When you sleep, during certain phases, your body gets paralyzed, and some people actually wake up during this phase, and experience what your daughter did. It is frightening but I do not think it is harmful. Sleep disorder people can tell you more.
With BP it is always smart to pay attention to meds. It usually takes a fairly long time to get someone adjusted. The meds all have side effects, and get changed frequently because of that. Also many of meds change the balance of the brain neurotransmitters. The brain initially resist this change, then relaxes and allows the meds to work, that's why it takes so long to adjust medications, why antidepressants often only work after a week or two.