My Index Finger Received A Burn A Few Years Ago

My index finger received a burn a few years ago close to the first knuckle and as a result I have a scar. Just recently underneath my scar I noticed my finger swelling. Over the course of the last two days it has grown so large I can no longer grasp or make a fist. When poked with a needle thick white goo comes out , and quite painfully I might add.No serious redness or heat associated with infection is present. What is going on and do I need immediate medical attention?