See if you had got some percocets or dilaudid your question would be very easily answered: start by popping a 5mg percocet, if you don't get high take another one. You won't die. If you're interested in the experience and that's it, you don't have chronic pain or extreme anxiety or depression, these prescription pills apart from some minor subtleties are going to provide you with essentially the same experience as heroin and I personally prefer them to heroin any day. There are so many benefits to popping a pill produced in a clean laboratory environment over sniffing some randomly chosen amount of an unknown quantity of diacetylmorphine, produced by some drug cartel or gang and passed down hand to hand adding cutting agents along the way, especially if you have no experience at all with opioids. Heroin is just plain filthier than oxy's or dillies. Of course there are fake pills you would need to watch out for but that's pretty easily addressed compared to heroin which is never pure.
There's another word for the paranoia that led you to make this thread: common sense. My honest opinion: dispose of it somehow and pick up some percocets if you're really that interested in the experience. But of course you're going to try it, and most likely really enjoy it. It sounds like you didn't pick up that much H, probably like 100mg of it? Disposing of it is the smartest thing to do, obviously. You're already second guessing yourself and I would not choose to ignore your voice of reason and apprehension.