A good and reliable auto-injector is made by B-D. It is called an INJECT-EASE 100.
It does skew the injection needle slightly up and away from the release trigger but that is minor once you adapt to it. I love it, it takes away the anxiety of the penetration scare and when it surges forward, it is all done. What a relief!Good luck.
Please let me know if I can be of any further support. Private email is welcome.