Joy, sorry that you and your daughter are going through this.
Unfortunately I don't have the answers..... Every BPer is different and the journey through diagnosis to treatment is different for us all.
Your daughters doctors may have an idea of what is wrong with her, but an accurate diagnosis and effective treatment needs for her to want to help herself. I think that's the hardest thing about loving someone with mental illness, they need to want to help themselves.
I would suggest that you try to encourage her that things can be better and that the doctors and meds can help life to be better. Encourage her to find out more about whatever diagnosis they come up with and to talk to people who have it.
Let her know that you love her, but set boundaries as to what is acceptable behaviour and what is not, you have to look out for your own health also.
Wishing you and your daughter all the best.