With bpd the personality is fragmented (meaning there are good and bad bits but not integrated bits (bits with both good and bad)). Because of the fragmentation there is a lot of
anxiety which the person tries to manage by ?? usually binge eating, spending, speeding, being promiscuous, self-harming, etc.
Medication doesn't cure it only manages symptoms.
I would strongly advise trying psychoanalytical psychotherapy.
There are dbt classes on the net if you want to check them out.