question: My 12 year old son within a 2 minute span had his left middle finger knuckle developed swelling about the size of a walnut. Earlier in the week he had hit his knuckle in which it was swollen. That went away and he has been playing baseball for the last 3 days without any problems. He says it doesn t hurt, however it is very large in size and fluid like. Any suggestions? or do I need to go in?