A trip to the local doctor confirmed this. Haha, that's a funny story. I went to the Dankook University hospital because it's on campus, and I get a discount for being a Dankook employee. Win-win right? Well, I went to the reception and asked to see a doctor. After getting an English translator on the phone, to whom I explained the injury, the receptionist refused to let me see a regular doctor that day. She kept saying 'Doctor, opsoyeo' which means there are none. But tomorrow, she said, finger specialist. All I needed was a proper splint (I had fashioned myself a makeshift one already out of cardboard and tape, but I needed a real one) and perhaps an x-ray to ensure there wasn't a fracture. Apparently this was not possible without a specialist's expertise.
So the next day I go to where she booked my appointment and I arrive at a sign that says 'ORTHOPEDIC SURGERY' - wait what?! All I needed was a splint and I got sent to a surgeon. In Canada, this would have taken months to get in, but here I only waited until the next day. Despite my hesitation, the doctor was really nice and he spoke English. The x-ray showed that the tendon had pulled away from the bone (over stretched) and he wanted to give it time to heal. He was very impressed with my makeshift splint and couldn't believe I had made it myself (it would seem no one in Korea takes health care into their own hands). He taped up my finger to a splint and advised me not to use it and come back in 2 weeks so he could show me 'finger exercises'.
Two weekends of Ultimate later (yes, I had to keep playing!), I went back to him. He took my splint off and buddied my middle finger to the ring finger to stop it from twisting. The joint was very stiff, but after stretching it all weekend (and playing some more ultimate - hehe) it is feeling better! Not 100%, but I can almost make a fist on my own. Hurray!
Middle finger sprain!