Hello there, welcome to RYL.
Sorry to hear that you've been self-harming again. It does seem likely that being off your mood-stabiliser could have been a factor in this. Did you come off it under medical supervision? Either way I'd recommend getting in touch with whoever prescribed it to have a chat about what's been going on.
Have you ever professional help for recovering from your trauma? If you haven't already, maybe it would be worth checking out
this thread for some ideas to help with flashbacks.