It looks painful, poor baby... I know my
chickens follow me around, VERY closely, and I've tripped over them, stepped on their feet, etc, and looks like as they get big
enough to free range, our ducks probably will, too. Is it possible that her toe got caught in a door, accidentally stepped on, or pinched, somehow? The thing is, once an accident like that happens, besides treating for the wound itself, we have to watch them carefully, to ensure bumblefoot doesn't set in. Personally, I'd keep her separate from the rest of my birds, in the cleanest, driest place possible, put a drawing salve on it, for as long as possible to draw out any infection (I think my birds wouldn't leave it alone for long, at all), then put a healing ointment on it, wrap it, and keep it clean and dry. With a duck, that's going to be tough, lol. I think you're doing well, with it, and it
should heal up pretty quickly.