What's wrong with people in this thread? Of course you shouldn't inject it. Ketamine is a powerful disassociative anesthetic, and if you don't know exactly what your dose is you can become unconscious easily if you take it the iv route. It's not dangerous, since ketamine doesn't suppress your breathing, pulse or blood pressure like most other anesthetics (that's why it's a WONDERFUL drug to use for surgery in catastrophic scenarios), but it can be very unpleasant.
Just pour the contents of the vial on a glss oven form, put in in the microwave and boil off the water. Scrape up the white salt and put it in a suitable container. Take a small knife and scoop up a knife edge of powder, snort it. You'll feel the effect in a couple of minutes. Don't do to much at once, or you'll end up in K-hole, which is a pretty unpleasant, highly hallucinative semi-conscious state.
I really really hope you didn't end up taking all of the 500 mg. If you did, I don't expect you to answer any time soon ...