I think you might be stressing the poor thing out more then you need to.Update: we've been applying the spray vegetable oil since Monday once a day. We are trying to get her to soak her foot for at least 20 minutes each day and see if anything is softening up. She hates it and tries to run away. The black areas are super hard and seem like built up dead skin. It looks like it wants to lift away but I'm not forcing it. So I'm hoping that maybe this is mites... but it there's not improvement by Saturday then I'm guessing it's not. She's still limping and laying down alot.
I would just use the spray and stop the stressful soaks.