im a crazy keen basketball player aswell. I dont think you will have broken your finger. Trust me you would know if you did. From your discription you have jarred your finger. Commonly caused by the ball coming into harsh contact with the end of your finger. Happens to me all the time. At one stage i have both the bottom and top knuckle jarred on the one finger. Hurts like hell, but you will be right in a few days. Strap it to the finger next to it, and you will be right as rain in 4-5 days. Dont let it stop u playing ball tho, its a hell of a game!
Good luck and high scoring
matt