I know :( If it helps at all I was varying the injection sites to spread the punctures, so would sometimes do it a little bit to the sides or lower down and it worked.

The other place or feline diabetes forums would be able to give more useful info

Edit: Ok it’s actually good to rotate injection sites and there are other ones than the scruff. If this saves you spending another $200 🤞 https://catbloomhaven.com/cat-insulin-injections/#step-3-choose--rotate-cat-insulin-injection-sites