We just got back from walking Jesse & Jake and noticed both dogs had raw spots on their pads. They just go shaved yesterday and I'm not sure if they nicked the pads or if it's from just being roughed...
Go to a pet store. There are various products available to put on your dogs paws to protect them from abrasion. Especially a problem if you dog pulls a lot on the leash when walking on pavement or other hard surface.