Hi...if this is a baby tooth, I wouldn't worry, it will heal on it's own. Just make sure he doesn't eat anything salty or spicy, and have him rinse his mouth a few times a day with warm salt water. If it's around a permanent tooth I would take him to the dentist just to make sure there was no injury to the tooth or nerve. Otherwise he'll be fine, and things like ice cream and popsicles are very soothing. Also, have him not brush that gum area, make sure he keeps the toothbrush off that area and just rinse well after brushing. I raised two boys and say several of these...take care.