I did a search but can't find the exact answer. I'm on my first pen so haven't done this before. Do you use the same needle to take the medicine out of the pen and to inject? Asking because i am worried what of some of the red rubber gets in the needle or of the needle is damaged by extracting.
Would it not be better to use 2 separate needles? And then maybe the one used to extract can be a bigger one while the injecting one stays as 4mm?
Any recommendations of where to get these online? Amazon is so full of shit I am not sure I trust anything from them...