Bro,
Chances are you will be ok, but bacteria can still collect on the inside of the pin where it screws onto the syringe. Hell, I know an idiot who used the same pin 7 times for drawing and injected all 7 with it too, and nothing ever happened to him. Just remember it is much safer to use a new needle each time, and I personally would rather spend the few extra pennies a new needle would cost then risk getting infected. LATE