I Have A Sore On A Knuckle That Has Become

I have a sore on a knuckle that has become infected - it is red, a little swollen, and is a bit white around the center of it. I soaked it in hot water yesterday and have applied antibiotic ointment. It looks a littel better - not as swollen and less white area in the middle. Shall I repeat the process? At what point should oral antibiotics be used?