FionaHi Julia,
Why not talk to your doctors as there are hormonal creams available which can be used rather than having the labioscrotal incision done. I only found this out from my gynaecologist when I showed her the list of operations I had had over the years.
It would be worth trying rather than having to put your daughter through surgery - wish it had been available 44 years ago.
All the best and God Bless
Fi.