How can i artificially cause eyes to become bloodshot?

Many ways: Anything that will irritate the eyes will cause them to redden. Actors use glycerin which stimulates tear flow and causes reddening. You could of course use pepper spray or bits of cayenne pepper. These are benign and will cause reddening and then when the effect is gone, the eyes normalize. Of course there are a lot of toxic and dangerous chemicals which will do this - not a good idea.