Looks like bumble to me. This is how it presented the time I had it. Caught it early like this and never developed a spot. I went to the vet, know that's not a choice for everyone but the daily soaks became too stressful for both of us.Are you all sure this is Bumble? Its not a round sore with a dark spot... Its just the color of its feet and sticking to the side of the heel pad and sticks out. I've just never seen it present like this.