I thought I sprained my thumb two and a half weeks ago, while mock fighting, it isn't healing.?

I was thrown off of a person while putting them in a choke hold on the ground during Krav Maga practice and landed on my stomach, hand tucked under neath and pressing my thumb into my hand. There was a loud crack or POP, instant swelling, and later bruising of the thumb muscle area that lasted for two weeks. The swelling has gone down but now I still cannot bend my thumb into my palm without feeling pain and tightness pulling it back out. Any suggestions? I would like to avoid going to see a "hand doctor" i don't even know what they're really called actually. Any suggestions?