Yep - loads of us get stroppy as a teenager (and they all are - notwithstanding diabetes, so he's no different!) (it's their 'ormones LOL) when we're high or low, and let's make no bones about it; you have it in spades with diabetes too.
You are only his mother, therefore you know absolutely nothing, obviously, and are probably the only mother who won't let him do whatever you won't let him do, because all his friends mother let them - yet funnily enough when he's 30 and talks to his friends he'll find out their mothers actually wouldn't let them do it either! - I know this cos I had a ma just like you, nag nag nag like a nun's drawers - always on!
And that is actually what 99% of all teenagers think about their mum though some are a bit better at not showing it !
Unfortunately I don't know what to suggest that helps, but know your place and be aware whatever you do or say - it will be wrong anyway - and don't take it personally!
Have you tried sarcasm or is he not sufficiently grown up yet to understand that? cos 11 now is about the equivalent of 14 when you and his dad were his age. Tell him you wonder whether he realises when he lands up in hospital when he collapses from abusing his body and gets carted off in an ambulance that they would put him on the childrens ward, stress that, he'll hate that idea! and you are only thinking of him every time you try and get him to test etc.
OR - would he be interested in a pump? - the Roche is good because the meter/remote Bluetooths instructions to the pump, and it can't do it's electronic wizardry and calculations UNLESS HE TESTS HIS BLOOD. Both the meter and pump can beep and grunt and vibrate - even plays tunes for certain things, but not like JayZ or whatever LOL - and anyone with the desire could make a most impressive display for their friends I'm sure, once they get their head round it ! Oh and the brand new version of it is out in July! Pictograms and stuff, not had one in my hand yet but it looks nice!