Duck cant walk

[agcbftw]

I need help. I have a 17 months old duck that out of nowhere she can't walk. She can move her legs, tail and everything but she cannot keep herself up. I notice a bump on her spine, as you run your fingers along it, it goes up about halfway then straight down, making kinda like an angle on her back. I also notiice when i put her in the water she is unable to stretch herself up, which makes me think she cant pick her front weight up which in turn could explain why she cant stand if her frint half behaves like dead weight. Vet already saw her and gave her steroid shot jn case it is a pinched nerve but nothing. Hoping somone knows what it could be except my worst nightmare which is an injured back