I lost three toenails, but not until the nail bed damage grew out some months after chemo. When they fell off I wore a bandaid for a few days until the skin grew less sensitive.
Wearing dark nail polish on them made no difference. They all got discoloured and had weird ridges. One of my big toenails still isn't quite at the end of my toe yet and has a bulbous ridge still. Can't wait until it's finally gone.
All my fingernails discoloured and lifted, but none fell off. They were ringbarked, a ridge for each chemo infusion. They've been tough as steel all my life but 10 months later, only two, the pinkies, have recovered. The rest are soft and bendy. I have to keep them very short as they split and flake so easily. I hope they recover one day.