My son had a bug bit on his shoulder and now little bumps are appearing around it and all over his upper back any idea what it could be?

Insect bite: Do you know what insect? If tick bite or spider bite or has a sick contact with similar rash should see a doctor but if not and If the bumps are slightly red or itchy but not getting worse ( increased swelling, pain, redness) and no fever, you can apply topical OTC neosporin to prevent infection and1% hydrocortisone for itching, on the affected area twice daily for 3-5 days. See doc if not better