I love the basics of the case made by @SSSR_SH_837849 but I needed one that was smaller and included a way to hold needles without everything falling out when I opened it so this is the remix. The original walls were pretty thin and there were openings at the bottom as well, and my makes kept breaking in my bag.
This will hold any insulin pen shorter than 6" and up to 0.8" wide, and most BD brand pen injection needles including BD Nano and BD UltraFine.
Other Materials:
This was made in both Tinkercad and on the plate in PrusaSlicer for more accuracy, and includes negative space, so the files aren't .stl as I needed negative space for magnets and the hinge. I used PrusaSlicer to add my emergency contact information inside the lid, and made one for a kid I work with with the Insulin logo on the lid; I've included the .svg for your use.
This works in both PETG and PLA; personally LOVING CookieCad Elixer PETG in Witchcraft
The author remixed this model.