I kinda skimmed through all this as best I could.
I'm glad you have a team you are working with, but it still sounds like you are in a cycle that needs broken.
It might be good to look at what you are trying to numb-out when you take the pills.
You might want to contact also SAFE Alternatives (S.A.F.E. Alternatives® | Locations). They specialize in self-harming behaviors. A psych hospital stay may be an option if you can't seem to break the cycle on your own. I wnet through a period of about a year and a half of progressively worse SI that constantly landed me in the hospital for severity. I finally entered a specialized program which helped a lot (I went to a trauma specialty unit). If you do go the psych route, I would suggest a program that offers therapy, not just med stabalization (aka: not simply a general psych unit, but someplace that can start to address the underlying issues).
Also, DBT may be the most popular treatment refferral for self-injury and emotion regulation, but it's not for everyone. If you are feeling that it is either not helping, or more triggering, I would urge you to keep asking for alternatives. I happen to be very triggered by DBT and it has become life-threatening every time I have tried it (well over 7 times because those I worked with were sure it was the only way I could heal). I found (for myself) that intensive therapy where I can address my triggers and what they actually trigger with the help of a supportive person is more effective than all the DBT in the world. I know I need to address my trauma before I can totally give up my self-harm. DBT can have some useful skills though, so if you can take any of the info they give you and tailor it to your needs, it can be a great resource. I never did find the behavior chains helpful. They felt demeaning and trivializing because I still felt horribly alone in dealing with everything.
keep trying and reaching out. And keep looking for alternatives that may be helpful when what they suggest doesn't work.