Just get it from the silk road if you don't know anyone in your area that's selling. You can buy needles at most drug stores - they're meant to be used by diabetics to inject insulin but they work fine either way. H isn't really something that you need to worry about 'set and setting' with. It can induce nausea and vomiting so you need to make sure that you won't choke, but that's really the only danger.
The risk of addiction is mostly caused by the fact that using heroin feels really really
good. It's like being wrapped up in the comfiest coziest blanket, made of fluffy clouds and sunshine, and having this deep-seated feeling of security and satisfaction and knowing that everything's going to be okay. It's such a great feeling that you want to experience it all the time, every day. That's where the danger comes from.