Hi,
You may find it worthwhile to try areas outside of the normal place where you get blood.
Sometimes I find I get blood more easily from just below the very tip of the ear.
And sometimes I get more blood if I move in a bit further, away from the very edge of the ear.
Be prepared to experiment a little.
Something else I've found is that, from time to time, I can get a little complacent and lazy, and my testing technique gets a little bit 'off'. When this happens the most common mistake I've made is to not put pressure on the
underside of the ear while I'm pricking the outside. The lancet needs something to 'resist' otherwise it can push the ear away rather than prick it. (I'm not suggesting that
you have got 'complacent and lazy', but it never hurts to revisit our technique from time to time.

)
I've been testing my cat for a long time now (over 9 years) and in his case the blood supply to the edge of the ear has shifted quite a bit over time. It's just a matter of following it...
I'm sure others here will have ideas for you also.
Good luck!
Eliz