I have 4 children and I used to give them a dose of childrens tylenol before we left the house to get their shots. You can put a cold compress on it and some of the tylenol for the pain. I know those tetanus shots really do hurt and the arm is tender for a while. Maybe a call the the dr wouldn't hurt also just for your own peace of mind. They will tell you if this is a normal reaction. Good luck! Your little man sounds very brave
