hi there, I am Dr. Deepak, I work in the Emergency Department, where i see many children s with head injury. It feel good to see that you are taking good care of you son. As you have mentioned that your son had walked into a pole and has developed a lump on the left side above the temple area near the hair line. you have applied ice and made him to relax, that s a good thing that you did. You can give him some pain killer for the pain, which can simple Paracetamol syrup. Following you just need to a watch on few thing Like 1. If he vomits 2-3 times 2. If he appears sleepy out of unusual during the day time. 3. if he has bluish colouration behind his ear, or around the eye. 4. If he complains of ringing sound in the ear or complains of difficulty in hearing. 5. If the bump is more then 5 cm. 6. If he develops a seizure, when he is not a know case of epilepsy. Then you need to take him to Close by hospital, and if not, Then he can play around as much as he can. Thank you Hope your concern was dealt with and your kid has a speedy recovery.