Honestly, from a writing perspective, my suggestion is: play into it. Your job as a writer isn’t to make life easy for your characters; it’s to provoke interesting interactions. Having a character who’s pathologically disturbed by the sight of blood, but engages in violence where he knows he’ll encounter it is not a bad thing. On it’s own, it’s a decent quirk, and it gets into an experience almost everyone can relate to; doing something distasteful, because it’s necessary. Also, an aversion to blood, because avoiding that stuff is a natural survival instinct.
I meant what I said, you have a weapon that’s designed to kill people by poking holes into them until they leak to death. There’s no real way to use that and not get blood everywhere.