Probably bug bites(maybe bees) or an allergy. If they seem to bother him, try Benadryl (call your vet for your dog's dosage and to confirm it is safe for him). If they persist, get a professional opinion.
I agree with KAL - it sounds like an allergic reaction to something, possibly insect bites. For otherwise healthy dogs, the dose of benedryl is 1 mg per pound of the dog's body weight. Hope your pup is doing better by now. :-)
The Content on this Site is presented in a summary fashion, and is intended to be used for educational and entertainment purposes only. It is not intended to be and should not be interpreted as medical advice or a diagnosis of any health or fitness problem, condition or disease; or a recommendation for a specific test, doctor, care provider, procedure, treatment plan, product, or course of action. MedHelp is not a medical or healthcare provider and your use of this Site does not create a doctor / patient relationship. We disclaim all responsibility for the professional qualifications and licensing of, and services provided by, any physician or other health providers posting on or otherwise referred to on this Site and/or any Third Party Site. Never disregard the medical advice of your physician or health professional, or delay in seeking such advice, because of something you read on this Site. We offer this Site AS IS and without any warranties. By using this Site you agree to the following Terms and Conditions. If you think you may have a medical emergency, call your physician or 911 immediately.