Take it to the vets
go to the vet and get the ear stiched.
Take it to a vet. or go to a pet shop and ask them what they think you should do for it.
I think you should bring your pet mouse to the vet when its sick: running nose and or coughing hard. Bring your pet rodent to the vet if it has loss of appetite or bleeding.
You can put a new mouse in the same cage as another, but if your mouse prefers living alone, don't put the mouse in the cage. The older mouse should be better off solitary.
mites
because it is ready to have a baby if it gets near a boy mouse
Causes internal bleeding.
Keep it warm overnight, and if it's still alive in the morning, set it free.
a mouse
Will another mouse eat the head of a mouse caught in a trap?
the sign of a mouse about to give birth is it isn't moving to much. another way to tell is if it has extreme weight gain. or there could be bleeding in the cage. make sure you put a lot of bedding where mom sleeps. another sign is if she's burrowing deep in the bedding. don't bother the cage in till one day after birth.
Possibly, yes. They occasionally canniblize.