In my microbiology class, dipping our tools in alcohol and then burning the alcohol off by quickly running it through a Bunsen burner was good. I never took any other classes even remotely medical related, so I don't know if that was sufficient for your use
But you should have sterilized the skin before puncturing, like wiping it with an alcohol soaked gauze pad or something.
The mirror shard would have dirtier than the needle, and it sounds like that didn't cause any problem.
I'd just keep an eye on the area, like if you notice any pain, or if it looks different than usual.
But why were you checking for pus 12 years later? Why are you risking an infection in order to check for an infection?