
I would for the time being keep her feet as dry as possible.
Grass etc is terrible for causing staining as the foot is wet so much. The problem with westies is the coat is white plus the have a hard coat so it soaks up any colour.
I am having a nightmare keeping my lot clean just now as it has never stopped raining.
Hibiscrub and Malaseb are quite good for lifting the stain. You can also try mouth gurgling peroxide. It is a very very small solution. Low enough we can use it as a mouth wash. You can pick it up and the chemist if you ask for it at the counter. Dipped in a cotton ball and the area wiped and washed after 1 min. The stain will take a few attempts to lighten. If you can keep the feet dry and there is no porblem IE chewing then it will grow out again.
Talc or chalk on the feet ( the night before the show) will help to hide it slightly.