Suggest Remedy For Swelling And Pain In Elbow After Injury

My son is 3 and half years old yesterday he fell from the 4 1/2 foot air balloon bar on the playground and landed on the air balloon surface. He immediately started crying but not able to move his arm and fingers. Within 10 nimutes his arm was swollen and very warm to the touch. We took him to the ER where they did x-rays and put him in a hard bandage for 07 days till his follow-up appt with an orthopaedic specialist. They said that it wasn't broken from what they could see but they couldn't rule out a hairline fracture or any muscle or ligament damage. It does not look bruised from the naked eye but is very visibly swollen when we remove his splint and he says his elbow hurts a lot when touched from any angle within 2 inches from his elbow. he says it doesn't hurt all the time but sometimes when he's laying in bed with his eyes closed ready to fall asleep it hurts. I've given him tylenol or advil regularly as needed and always right before bed to keep the pain away. kindly advise treatment? Thanks for your help.