Re: Sharp pain in 2nd metacarpal
Which bone is the second metacarpal? Is it the bone that is part of the palm of your hand?, or is it the bone that makes up the first part of the actual finger?
Best bet is to see a doctor asap. If it's broken you'll want it taken care of, and if it's not you may be able to get away with just ice and rest and you may still be able to fight depending on the pain.
Don't mess around with your hands, they're important for boxing as well as for everyday life.