Hi,
A lump behind the ear in children could be due to throat infection, insect bite, accidental trauma to the site, ear infection , etc.
Lymph nodes in the region are known as post auricular lymph nodes and can enlarge secondary to infection, inflammation, etc.
You could try some warm compresses at the site, warm saline gargles for his sore throat and some oral antihistamine medications for the swelling.
Does he have any other symptoms of fever, etc?
If the swelling still persists after a few days, it would be best to consult a doctor for a clinical examination and whether a course of antibiotics is required.
Let us know if you need any other information.
Regards.
Try a cold compress for the swelling and discomfort and tylenol for pain of course due to the ear factor watch for sighns of injury eaqrs are sensitve poor little guy hope he is okay and all goes well
Well as long as he seems fine then he probably is. Look for signs of a concussion such as wanting to sleep right after. Check his eyes for any changes like dialation. My kids have gotten plenty of goose eggs so don't worry. Sometimes if they hit it in the right spot it can be pretty big! Best of luck!