What Is The Treatment For Pain In The Toe?

Hi, a couple of weeks ago I had the misfortune of kicking a goalpost, with my right foot in an attempt to clear the ball in a game of football. Needless to say it bruised very severely on my right big toe and caused me a great deal of pain. The pain has now gone but the bruising remains. Tonight, after playing football again (now the pain's gone) I found that there was a sticky, black fluid coming from a pocket on the left hand side of the toe nail. What is it and should I worry?