Injection

Injection through clothing should be avoided by all means, since fibers from the tissue or dirt could reach subcutaneous tissue. This could lead to painful infections that are completely preventable with hygienic injection. Another disadvantage is that the extreme sharp cut of the pen needle tip could be bent while going through the clothing and thus the injection will get painful.
The injection site should also be controlled for blood or insulin residues after each injection, which is not possible when injected through clothing.

One should pay attention to

Single use of the needle

Pen needles are single use products. Use a fresh needle for every injection – for your sake!

To use a pen needle multiple times can lead to undesirable consequences:

Pain, because the gliding silicone coating was used at the first injection
Pain caused by a blunt needle tip
Inaccurate insulin dosage and blockage of the needle by crystallized insulin remaining from previous injection
Lipohypertrophy by tiny injuries at the injection site

Correct needle length

If the needle is too long, insulin could be accidentally injected into the muscle tissue

Remedy: the right needle length is determined during the diabetes education

If the needle is too short, insulin could possibly flow out through the tissue pressure and cannot achieve the required effect

Remedy: the right needle length is determined during the diabetes education