Toto's nose did this also. The vet said it's called "Snow Nose" and there was absolutely nothing to worry about ... she said her dogs have it also. It's caused from lack of sunlight, etc. She did, however, tell us to watch for other spots around other areas that are normally black ... eyes, lips, etc. Sometimes it's an indication of other problems going on. The one on her nose is the only one she has ever had and sometimes it gets darker.
