Insulin drops in the pencil

Hello
I started to get Apidra a week ago, I started with very few units.But I have realized that when I get the pencil there are always a few drops which makes me think that if I inject so little, it may not get everything or that it is even that is why I have to correct later.How long do you have to leave the needle inside before?Do you have to exhaust the pencil before?What consists of the pinch theory that I have read somewhere.I'm sorry but I'm new and I need help, my educator explains it a bit fast and these doubts arise.Thank you

Before clicking you you always have to discard a unit or two until you see that liquid comes out to purge the needle.Then load the ball with the dose you have to put, take a pinch and click.You squeeze well so that everything comes out and leaves it for a few seconds punctured so that all the liquid will come out without stopping.How much I don't know how to tell you, I usually leave it about 5 seconds or so.
The pinch is so that the needle does not reach the muscle and is in the layer between the skin and the muscle.If you click on muscle it takes effect much faster and stronger so it can give you hypoglycemia.Especially with the slow one, which are more units can be dangerous.Depending on the puncture area and the fat you have, it will be easier to reach the muscle.For that there are different lengths of needles.Ask for the ones that best adapt to your case.

Thank you so much!!I didn't know how to discard units !!Not everything else