Get out of the pen with a syringe

Hello good!!!Let's see, many times, I have had figures to say, if I inject 3 I get too much, and if I inject 2 I do not reach the target value, and what I have done is to take it out with a syringe from the pen, to othersThat in a few units, the pen does not behave well.
Well, my question is whether you do it or not, and when you do it if once the units have been taken out, then you select in the roulette and oppress the button to avoid the empty effect.
Another thing ... Air usually enters the pen?When I leave the needle, it is a pass, since some insulin comes out and enters air, because of insulin differences, and I continually have to be taking out the air, will that influence the injections and the selected units ???

Thanks Compis!

Leave the needle ??Needles are of a single use.Not to use the same all day.Primarily due to hygiene, second because its edge and tip in a single puncture deteriorates and reuse that needle more pain and discomfort when it comes to nailing .. I do use the lancets for more than one use and change when IAgreement or gives me (badly done because they are also of unique use)

I already know ... but I usually use them a couple of times or three ... I have to unlearn what I learned

Well, in our case we ask insulin, sometimes in vial and sometimes in Boli, and at home use the syringe.
And yes, I still trust much more than the syringe than the ball.

Air?I think it has happened to us all, I always took it out when I saw.The issue of pushing a unit or two before selecting the units always.

You always have to purge, not only when you see a bubble, always.And you have to change the needle to be possible in each puncture.At first glance it is not seen, but it deteriorates a lot.

@Anaisabel if I know, but when you are working and according to what situations it is a curious move hahaha