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...
Could be many things. If the pavement is especially hot, shoes will take care of the problem. Since I run my dog with my bike I added shoes after he had sore feet last year. Now, if were running on hard surfaces he gets his shoes.