@KitKat187 I would recommend checking/replacing the pads each evening depending on how active your hen is and if the weather is very wet. The cover plaster helps a lot but sometimes the pads can slide around and end up in the wrong spot. Changing the dressing each evening is good because you can do an epsom salt soak at the same time and make sure the area stays clean.
The skin will lighten and soften as the salicylic acid takes effect, much the same as when we treat ourselves. Sometimes it can take several days/a week to soften enough for the bumble to lift out.