Small red pimples with scabs on the dog may be caused by skin diseases caused by parasites, mites, fungal infections, etc. You need to check whether there are parasites on the dog, then give the dog a bath to deworm the affected area, and Apply fungal ointment and wait a few days to see if it improves. If it does not improve, you can take your dog to the pet hospital for examination to prevent the skin disease from getting worse and spreading.