So ill be starting up some of these injectable vitamins for the first time ever this Sunday. Ive read a ton about how you need to put the pin in, and then pull back on the lunger to see if you draw in any blood. If there IS blood, then you need to pull out and start over with a new needle, etcetera. How many of you do this? How common is it to hit a large blood vessel when injecting in the proper places?