I'm BP also. Are you in therapy? When my son was younger he was a head banger. One of the things we had him do is put his open hands on the sides of his head between his eyes and his ears on his temples and press down. It doesn't leave marks, doesn't look as odd to people around, and is a good step towards quitting.

As for the suicide urge I would suggest looking at an intenveive out patient program or a partial hospitalization program.