Every diabetic should carry one of these in case of hypoglycemia: a glucagon emergency kit. The one pictured is by Lilly:
They expire periodically, so make sure you get a new prescription when it's needed.
The problem is that there is a lack of adequate education on how to use one. You won't be the one to use it, so it doesn't help much for just you to know how — if it's needed, you'll probably be unconscious, or at the very least incoherent.
In other words, you need to be sure to educate your family and friends — people who may well be nearby if you have a dangerous low blood sugar episode.
But how do you use these things? It's not like you get a practice run, and Lilly's instructions leave much to be desired. So far, the best instructions I've found is this step-by-step slide show for the Novo Nordisk glucagon kit.
What I'd really like to see is a video of how to use one of these. YouTube would be nice, because then I could embed it in my blog, but there doesn't seem to be one of those. I'll keep looking elsewhere, and let you know if I find anything!