Poor little lass..
She been dumped with something that she has to manage, doesn't have a choice about and I suspect feels like it's totally controlling her life.. She lost control of her life with the excpetion of being in the control whether she does or doesn't inject do her BG's... And no-one understands what she going through..Her life has changed, she has no control over this change, no choice but if she ducks her head, don't inject or do her BG's then it can't control her...
Nagging her, showing her pictures or telling her what might could happen if she doesn't take the bull by the horns and start being proactive in controlling it all, isn't going to be effective at all, I suspect she already knows this, and is very scared young lady indeed...
How does one encourage, support and show a child that yes you can gain control, and enforce it to live the life you want to live and not be at it's beck and call! As with all teenagers what the hell do us adluts know at the best of times, you just don't understand etc etc...
A good idea if she game for it, is for you and her mum to mimick, being a diabetic for a couple of days, do the hog, BG testing (pretend or fresh lancets for each) pretend to inject, work out what dose you would need to match your needs, look at where it effects you day how it all fits in with social life etc.. This will give you a gest to what she's facing, and hopefully you may not quite understand but you trying to..
I would also ask about counselling as she is stuggling to come to terms with it all and how it is and will effect her life... There maybe fears that shes unable to explain to you but might be able with some-one else first...
I would also ask if they know of any other diabetic of similar age that will talk to her, and perhaps a parent or two that you could talk to...
Another consieration might be an insulin pump, it a different regime and a slight different method of control but it can give her the believe that she can and is in control of her condiditon..