A woman was lying in hospital:
She had a scalp wound which even the cheerful nurse described as
‘quite nasty’; all her hair on the left side of her head was
shorn away’: and sixteen stitches had been put in.
Does it mean she had a wound from which the skin had been removed?
What had been shorn away was her hair - presumably not as a direct rusult of the accident, though. The doctors/nurses needed the area around the wound shaved, so that they could stitch it up properly (and apply a dressing).