That's a shame. But yes, the pedes here are pretty tiny.It looks badly injured, and I am assuming it is really small? If so, I don't think anything can be done.
Arthroverts
Unfortunately, this one didn't make it. From what I could make out, it was a pretty deep injury.My millipede just did this exactly for a week before popping out of his old exoskeleton as good as ever. I'd move him to a smaller setup (a cup with a lid works fine) with fresh moist substrate and let him be for a few days.