Even if the two are not directly linked, it would make sense to have the urge to self-injure with a background of bipolar 1. You're in emotional distress, and typically people will self-injure because the physical pain helps take away some of the emotional (not for everyone, just from what little I know and have experienced with SI).

I would suggest talking to someone about it, a therapist if you see one and are comfortable talking to them about it. Or if not, you can talk to me, I don't mind at all. But please don't hurt yourself <3