Hi!
Okay, first, I admit I began by going back through your posts so I would know more about you and your glider's situation.
To my knowledge, over grooming her tail is most likely due to stress. (Although as you've stated, she has serious health issues). So if it's stress, the question is, what's stressing her? Is the other glider you own still being a bit overly-dominant with her?
I guess I'd say try to figure out what is stressing her. My glider over groomed her tail because she was in a cage next to my quad, and that stressed her. As soon as I moved her to her own space, she stopped over grooming. (And eventually she got her own big cage and a cagemate...long story short) if you can't exactly give her her own space, maybe more pouches in the cage and more toys for the dominant glider to keep busy and more feeding stations. It's really hard to say without knowing what's stressing her.
Hope that helped! Keep us updated.
Oh, and no, I wouldn't do neosporin.
And I would try to figure out what's stressing her before I amputated (that seems so extreme). I would consider amputation only if she were breaking the skin and causing injuries that won't heal.