This skin infection is usually seen in puppies less than one year of age. The areas most often involved are the chin and/or abdomen. Staphylococcus bacteria are usually present and thought to be a main cause of puppy impetigo.
Impetigo is used to describe small areas of infection found on the hairless area of the abdomen (belly). Small areas filled with pus (pustules) can be seen. Often, these pustules break and form crusts or circular areas of scaling skin.
Impetigo in puppies seldom creates more than a localized area of infection. It is not life threatening and some mild cases may resolve on their own. Rarely, the infection can spread and become deeper.
Hydrogen peroxide, chlorhexidine, or benzoyl peroxide applied twice daily will usually clear the condition. Excellent benzoyl peroxide shampoos are available to treat this condition. In severe cases, your veterinarian may prescribe antibiotics, to be given orally or topically. Most puppies outgrow the condition. In Doberman Pinschers, Bulldogs, Boxers, and Chinese Shar-Peis, impetigo may persist into adulthood.
From what you're describing, I think it isn't that, but it is best to consult your vet.