hello all newbie question here. ok I am getting much better with this whole new word I stepped into with pinning. I had something strange happen tonight. I pin in quads. I have no pip yet what so ever no redness sores pimples or lumps. I am pushing 1.2 cc every 72 hours. My question is tonight when I pinned I slowly stuck the pin in, I always do it really slow rather then a quick stab. I was in 1" to 1.25" I use 1.5" pins and don't go all the way in incase of a broken pin, nice to have something to get a hold of to pull it out. well I did a draw back to check for blood and air came in the barrel. freaked me out bad so pulled out made sure needle was tight and pushed air out restuck and good to go but my question is where did the air come from? everything was gtg but I pulled air when checking for blood. I am a perfectionist when it comes to things so I would really like help on the matter. also what would happen in the same spot is pinned everytime? I rotate between muscles on quads now going to do calves next week to try something new.