I have 2 year old Cleveland Pears which have some of the bark rubbed off by...
To address tree damage, trim loose, shredded bark where it's not connected tightly to the trunk. Where the bark isn't loosened around the circumference, the tree might heal and continue to develop. Fully girdled trees will die. If limbs have been broken, then the tree's structure may be altered. Prune broken branches to a strong side shoot or main branch or trunk. Look for an undamaged shoot close to the top of the tree that might be trained as a new leader if the tip has been broken off. If nothing is done, the tree will re-sprout in the spring below the damaged area, and become shrubby in growth and appearance. Over the course of the growing season, new bark will develop to cover exposed wood.
Research has shown that when trees are damaged in this way that it is best to leave the wound open and to the air for this will allow it to heal the best. 20 years ago it was suggested to use wound paints and wraps but research and experience proved that these materials allowed for secondary organisms and insects to hide and invade under these and slowed the healing process.
Here is a fact sheet that explains how to protect from deer and the damage they cause.