I got a question. I read that you should switch the needle on the syringe before injecting it because piercing the vial to draw the oil out dulls the needle and it is tougher to piece the skin and can cause and abcess. My question it how do you switch the needle? Does it pop off, screw off, etc? Are all syringes made to switch needles or only certain ones? Any help would be appreciated. Thanks -K