Oh my goodness, this does not sound good at all. Best to have vet examine to determine the cause. You don't want these sores to become infected. Wash with sterilized water and baking soda or just plain salt. Salt is an antibiotic when added to water. This puppy sounds like it need immediate attention. I would not waste time, maybe if you can't afford vet, contact local pet shop or animal shelter as there are many professionals available to help
