UG, re-sterilize your gear systematically; alcohol wipe, poke a needle in, remove plunger (to avoid pressure buildup), oven cook at 225 for 15mins or so... always put vial in hot water 3-4 mins before injalways pull with one needle then swap with a fresh one before injecting... don't breath in the needle direction.Don't use water based unless absolutely necessary. all shit I read online .. hey I'm a gear guru now..
Also infections can be caused by dirty ass gear contaminated with bacteria.