Is this injector toast?

While trying to replace the o-rings on my fuel injectors on a 1997 Taurus, 3.0L OHC U engine, I cracked the back retainer ring part of the plastic tip of one fuel injector. The ring won't go over the rest of the plastic piece but I don't know if it would either leak, eventually break loose or just be OK. The rest of the plastic tip is fine, no cracks.
Should I use it or buy a new one? I am replacing head gaskets and the new o-rings were in the gasket kit but I probably should have left the old ones on. Thanks for your help.....!!