I change out the needle but don't discard whats in the barrel. Why would you,its just your own blood? Never had any probs doing this.During the aspiration if you do hit a vein and you see blood and have to re inject will you have to use a new needle? Also will what you have in your needle be used or will you have to start all over and discard whats in it?
It's important to explain why. When you first open a needle, it's the sharpest it's ever going to be. Once you prick your skin, it's blunted. You can use it again, but it may hurt more as it's not as sharp... though I've done it a few times in the past. It's important to wipe your whole area with a alcohol wipe.
I'm sure you know to use a different needle than the one you draw the oil with. You can save that needle and draw with it many times.
The majority of abscesses are septic (i.e. caused by an infection) but sterile abscesses can also occur which are not caused by germs but by non-living irritants such as drugs.
I would get 3cc barrels with 23G 1" needles on them...use that to draw..then change that out with a new 23G 1" or 1.5" (or whatever you prefer) and inject. If you aspirate blood: pull out, change needle, and try again.
Tissue damage from needle will not cause an abscess. Abscesses are infections, an inflammatory response to a pathogen.
I would not recommend saving a needle and designating it as the "drawing" needle...why would you want to stick a dirty needle in your sterile gear? Incredibly stupid.
To CMP007, you will notice a huge difference by changing needles. In fact, I can't imagine how you've been doing it thus far without swearing to high heaven every time you used that needle you used to draw. Anyhow, I always used my thigh, which has no surface nerves so you don't feel any pain any way.
Like I said, tissue damage from a needle will not cause an abscess.
I realize the existence of sterile abscesses, had a couple myself, not what I was talking about.