Brandon,
Welcome to BPDR! We're a pretty nice group here and the primary focus is on recovery work. From the sounds of it, you might have wandered into some of the NON discussion boards. Those places can be a little rough on folks with BPD.
It sounds also like you're a perfectionist with wanting to understand things effortlessly the first time through. Life doesn't work like that, not for everyone, not for all things.
Have you had a chance to look through some of the Tools (left-hand side) and some of the content on the main site (HOME link upper-right) yet?
There are some good things there that might help you ... specifically the Separation of Stuff area and the Ten Forms of Twisted Thinking (as well as the Untwisting part, of course.) I'll see if I can get the Self-Help for Self-Injury content back up there in the next couple of days (we were hacked & had a software switch a while back & we're still getting things back in order.) In the meantime, I would also suggest:
http://www.siriusproject.org/basics.htm - it's run by a BPDR member and it's been up for a good number of years. They're stable and very nice folks.
I hope you stick with BPDR too, though. Because I think a lot of the urges to cut can be diminished or eradicated through your BPD recovery work.