Mother dog just bit a pup what should I do?

The mother is a Chihuahua and the father is some kind of poodle mix. The cubs are about 3 weeks old barely opening their eyes. Of the six, she attacked one. I guess she had a chewing faux bone as all our dogs normally chew on and I guess just right now, the puppy was looking for milk and then he ran into the bone next to her neck where she had put it. She took it as the pup was going to take it and attacked him, now she’s licking up all his blood. There’s an injury near his nose and some blood from the mouth. When he breathes in or out, (I can’t tell which) there’s that sound of bubbles in a tube kind of sound (I think it’s blood) The pup is breathing calmly now and the mother is licking her pup, and I immediately took her bone faux away. Any advice here? Will she attack them some more? This is her second litter in two years. Poor little fellow :(