She may lose that toe in spite of your efforts. Her immune system may be working at cross purposes with the treatment she's getting. If her system is walling off the infection by decreasing blood supply to the toe, healing of the tissue will not be possible.
Just understand that what's happening is how chickens are designed and has nothing to do with the quality of your care.
What to do? Just keep the foot as clean as you can, and be prepared for the toe to lose its blood supply, turn black and fall off.