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So this is killing me...
I read the book some years ago.
My premise was that I do not read enough different authors, so I started picking books at random going down the alphabet.
This book was pretty far down the shelf of my library at the time, close to "Zhan".
The premise of the book was that medicine is bad, in prolonging life unnecessarily. So all medicine was banned.
Our young protagonist finds a medic bag in an old ambulance, and starts saving people. Leading to some unfortunate consequences.
It was called Dark Wing, or Night Wing, or some such.