Did you validate her feelings of being humiliated, betrayed, angry, heartbroken and embarrassed? Can you see how she would feel that way?
Said she can never be around my family now. Said that I was so stupid how that label will never be erased from my parent's minds, and that they will always judge her. I tried to explain that no one is judging her and won't,
Telling her that no one is judging her, after she told you that she felt judged, might have been perceived as invalidating. She felt that she has been labeled and judged. If she does suffer from BPD, then her feelings are her reality. By telling her that no one is judging her, you are telling her that her reality is wrong.
Based on what you wrote, she gave you a lot to work with. You were given insight into what she is/was feeling. You don't need to agree with her feelings, but accepting that she feels that way will go a long way to helping. We all feel things, others may not understand why we feel as we do, or agree that we should feel what we feel, but it isn't their place to tell us that our feelings are invalid. When we do that to someone else, we are, in fact, judging them. Because pwBPD feel emotions more intensely, the effect is magnified.
Do you think that it would help, at this point, if you validated her feelings? Let her know that you are hearing what she is telling you and allow her to openly discuss how she's feeling without interjecting your own thoughts and feelings?
Listen with Empathy is the first step in not invalidating others.
I know how hard it is to slow down and listen when being the focus of the rage. I failed so many times when I was trying to learn the skills taught here. It's natural because we feel attacked and thus the need to defend ourselves.
What might have been happening though is that she felt shamed and imperfect. Because it's so very hard for pwBPD traits to deal with those emotions, she probably was projecting onto you by telling you that you betrayed, judged, embarrassed, and humiliated her.
What do you think?