Hi Papillon11,
Warm welcome to the site and all the support here
One of the best skills to learn in terms of communicating with someone who has BPD is validation. When you have a chance, take a look at some of these conversations other members have had about validation (click the green links below):
I've been reading a book about BPD in teens and the author (Blaise Aguirre, MD) says if parents only learn one thing, it needs to be validation.
Let us know if you're able to try this with your D, and how it works with her. Validation can be counter-intuitive, so it helps to work through it if you feel stuck. It was a life-changer for me in my relationship with my son. I can't say enough about it and I hope it helps lessen the conflict in your interactions with your D.
LnL