L.L.
L.,
There is a good chance that when your baby was hit it caused a small cut inside his nose that continues to open up and bleed. Take some neosporin and put it on a qtip and rub it inside his nostrils, this will keep it moistened just like if he had a cut on his leg or somewhere else. Make sure that he is not rubbing at his nose or putting his finger up it as this will increase the chance of the scab coming off. Keep using the neosporin 2-3 times a day for 4 or 5 days and it should make the scab heal up. If it goes on after that I would go see a doctor just to make sure nothing else is going on.
L.