Accountability and compulsive lying

I am new to this site, to any site really, but I am at my wits end. I wish I could say that BPD is ruining my relationships and causing all the bad in my life, but that would be a lie. I am the one who is ruining my relationships. I cause all the bad.
That being said, it feels like I’ve lost control of myself completely. One small thing happens- change of plans, running late, etc- and it feels like my life is falling apart. Almost like everything is shattering in front of me. My body starts burning inside and it’s all I can do to not scream and slash into my skin. When this happens, I say things I know aren’t true just to cause myself more hurt and cause more conflict. I’ll bring up something my boyfriend said when he was mad at me (because I undoubtedly caused him pain or caused conflict) and I’ll twist it in my head into something bad. I.e. if I was having an episode with angry outbursts, he might say he’s going to go have dinner or go enjoy his night away from me. I’ll bring it back up and say that he went out with some girl and he’s messing around and cheating on me etc etc. I lie about things that don’t matter, and I’m not sure why I do. Everyday tasks I will lie about. I regret it as soon as the lie leaves my mouth, but I just run with it and never admit to lying even when the other person calls me out on it. It’s almost like I don’t have control over it.

I am hoping this site can help me with my personal accountability. If anyone has any suggestions on how I can stop compulsive lying, or anything that has helped you with accountability and angry outbursts, it would be greatly appreciated.

I do that same thing. Lie about mundane things. I would start with therapy. None of this is easy. But if you work on the issues with your past that caused some of this it can help.