There’s also not too much difference where you pin, too deep or too shallow. If it’s inside your body, you’ll get the drug, and the pain is related to 10 other factors. Now you start getting red and burning hot around the inj site as well as chills w fever, than you got an abscess.
One way I’ve never got one in 10 years is 1 needle, one extra tip, 2 alcohol swabs minimum. Swab each vial tip prior to drawing. Draw with one top, pull off and swap out for a new needle, typically 25< gauge. Use the leftover vial swab to hit your area you plan to inject. Than break out the new swab and hit it again, circling middle outward. Pin deep to the base of the needle. Use swab to stop any bleeding.
I leave all my gear in a black bag and never leave it in the bathroom, anywhere too hot(80+ degrees) etc etc. Forgive me if this is all rudimentary but it doesn’t hurt to have a refresher.