Many times a yellow lab will get what we call "snow nose" this happens in the winter-usually the nose turns pink or some of the area may turn pink. In summer, the nose turns black or close to black. Yellow labs are more prone to this, but can happen in other breeds too. I would at least call the vet and ask, they will tell you to bring her in, but that is O.K., as that will ease your mind. Is your lab outside and if so is it cold where you live? Aggieone
What is she drinking from? If I remember correctly, a yellow lab's nose can turn pink if it is drinking from a metal water bowl. Or maybe it's if it's not drinking from a metal water bowl... I can't remember. My light colored hound had a black nose when she was at the shelter drinking from a plastic dish, then it turned lighter once she was with us a few months, I figure it's because we use a metal water bowl.
I can't tell from the photo if this is a simple scrape or something else. My dogs scrape their noses sometimes when they decide to go into digging mode. I just wipe it with peroxide every so often and it heals up fine.
It wouldn't hurt to have your vet evaluate it. Dogs can get skin cancer and benign growths just like humans. And just like humans, dogs with lighter skin pigment and coats are more likely to develop skin issues. He looks like a handsome little guy from what I can see of him. If he were my dog, I'd take him to the vet.