I'm guessing you mean the chick has pipped the shell and you can see blood on the membrane where it has pipped? That happens when the chick pecks through a blood vessel in the membrane that hasn't yet dried up. Sometimes the chick will bleed to death, sometimes it will be just fine. Can you see any movement? Hear any peeping? Best thing to do is.... well, nothing.... as you can't really do anything to help the chick at this stage.
If it's any reassurance, I recently lent my bator to a 7 year old friend, who got a bit over excited come hatch time, and tried to 'help' a pipped chick out of its shell. She peeled off a small chunk of shell, the egg bled quite a lot, she put it back in the bator, and it ended up hatching out just fine a day or so later.