It depends how deeply the bark has been torn away. If the tough outer layer is all that's been damaged it should be OK. If the next layer that supplies the
tree with its nutrient, (i think it's called the cambium layer) is completely gone you could be in trouble. Painting damage is to prevent fungus getting into the
tree and is generally discounted by modern methods as it may prevent the damage from drying and scabbing as well as it may have. I'm inclined to agree with the mulch and feed suggestion though if the
growing season for the
tree is over i'd go easy on the feeding.