He could be having a reaction to fleas, flea allergy dermatitis. I would look her over well for fleas or flea dirt and treat her appropriately. He would also benefit from a good bath in a medicated shampoo with antibacterial properties for dogs. I am suspecting that a staph infection is present resulting in these lesions. Staph naturally lives on the dogs body but can become overabundant in areas creating these sores. It is commonly seen in dogs with allergies that affect the skin. Dogs suffer from allergies just like we do. It can be to food, pollens, molds, dust, and fleas to name a few. If a staph infection is present the veterinarian will want to treat with an antibiotic like simplicef for 7-10 days. He may also prescribe a medicated bath like malaseb shampoo. If he feels allergies may have triggered this than antihistamines may also be started. You are right, it isn't nothing and it is also probably really annoying for your boy aswell. If you feel he is really bothered tonight you can try and give him benedryl. The dosage is 1mg per pound of body weight.