How did hound get red bump on muzzle?

Dear Dr. John,

We are relatively new to the area. Our two dogs are adopted hounds, and our female dog is now almost seven years old. She suddenly developed a raised slightly red lesion on the top of her muzzle behind her nose. We don’t see any scratch or hole. Might you have any thought as to what it might be? There is a pond behind the yard, and she has been digging a lot back there and sticking her nose into the soil so we wonder if there could be something in it that might have triggered a reaction of sorts.

We are treating the lesion with Neosporin since it is both an antibiotic and anti-inflammatory. How long should we give it before we call the vet? Do you think we should be overly concerned? M.F.

Dear M.F.,

The fact that the lesion cropped up in just two days suggests that it is