Hello and

It's not surprising to hear that your daughter is struggling with more than "just" an eating disorder. It's good that the ED treatment team clued you in that there's possibly more going on.
Can I ask, how old is your daughter? In some US states, minors have more "say" over mental health treatment, while in other states, it's fully up to the parents... depending on ages.
Has your daughter been mostly compliant with the ED treatment?
And has the ED team made any recommendations or referrals for a BPD-specific professional?
...
A great place to start looking, if you haven't gotten any referrals, is the
Psychology Today "Find a Therapist" tool (should be a search box in the middle of the page). You can tailor it to your area, in person or remote, BPD specific, etc.
We also have some articles especially for when
your teen or adult child has BPD, definitely take a look at those when you have a moment.
...
Who else is in your family -- spouse? other children? How are they all doing... and how are you doing?