We experienced some bumblefoot last spring. It may be too late for your girl but what our vet had us do was to make an iodine solution in a 5 gal bucket. I put a bunch of rags in there. I then took one of those shoe/boot mats and layed the rags down inside it. I laid a bale of straw along the length and put their food bowl at the end so they had to walk and stand on the soaked rags while eating. I put their water on the side of the bale because I didn't want them diluting the iodine solution.
Here's a picture of one of my "hospitals." You can see the bale of straw the goose is standing on. Lower left part of the picture is the mat with rags...I put the food bowl inside a blue plastic box that I laid on its side so they wouldn't stand in it or dump it. The water is lower right. This particular hospital did not work well with the goose, but worked great for the ducks. It took six weeks for the ducks to clear up. This was after the vet had cleaned out the cottage cheese like bit of the infection.
It sounds like the infection your duck is experiencing has become more infected. I'm not sure if this same sort of set-up will work. You may want to make an iodine solution that you manually soak her feet in a few times a day.
Here's a picture of one of my "hospitals." You can see the bale of straw the goose is standing on. Lower left part of the picture is the mat with rags...I put the food bowl inside a blue plastic box that I laid on its side so they wouldn't stand in it or dump it. The water is lower right. This particular hospital did not work well with the goose, but worked great for the ducks. It took six weeks for the ducks to clear up. This was after the vet had cleaned out the cottage cheese like bit of the infection.
It sounds like the infection your duck is experiencing has become more infected. I'm not sure if this same sort of set-up will work. You may want to make an iodine solution that you manually soak her feet in a few times a day.