I have always used a 23 gauge 1.5 inch pin when I shoot one and a half ccs for the last decade. Because of frequent shots I ordered 25 gauge 1 inch pins this time. The shot barely hurt (almost felt like a slin pin) when I injected it in my delt but when I pulled it out I saw some oil leaking along with blood at the injection. Any advice? I'm sure It was pushed in all the way in.