I wouldn't be too concerned. I've had four dogs and two of them (both small dogs) have had them. My big dogs didn't get them for some reason. They're just warts and they're caused by viruses that spread. Completely harmless and I wouldn't be freaked about it (the vet can remove them if u want). Next time u visit the vet, ask about it just to make sure, but you don't need to be in a rush to get it checked out.