I think there may be two separate issues here (that may or may not be related):
One, the prolonged sting that takes place a few minutes after injection and lasts 15 minutes or longer for some.
And
Two, injection site pain at moment of injection.
Correct me if I’m wrong, but based on what I remember you writing, you have only experienced the 2nd of these “stings”. If that’s the case, then that’s probably why amo is not giving you a refund, as perhaps they believe that the prolonged stinging to the the only issue they offer refunds.
Yesterday my RS dosed and made sure to inspect the needle afterwards to see if there was any bend to the tip. There was nothing noticeable to the eye, but RS admits a magnifying glass would be better served to make this determination. Still, RS experienced none of the site pain upon injection (maybe a minor bite) but did experience the sting about five minutes post injection lasting for about ten minutes.
I think there are two separate issues here:
Possible bent needles causing injection site pain, and some kind of chemical leftover from the process causing the post injection prolonged sting.
For what it’s worth, Amo agreed to send me new product without me having to destroy my vials. If anyone knows of a testing place that could ID the sting, I’d happily send in one of my r10s: