young crabapple in danger

I hope someone can tell me what the best course of action might be. I planted a Sugar Tyme crabapple in my yard. It was about 7' tall when I bought it from Lowes, and it's only been in the ground about 1 1/2 months. I mulched around it (with a 4-6"  clear space around the trunk so the mulch wouldn't touch it). Last week, it looks like I had a deer rub off a moderate portion of bark and all of the leaves from about 3 branches. About 75% of the leaves and branches remain, but this little tree is very young and fragile. I'm worried it's not going to make it. I put up some fencing around it to keep deer away, and it wasn't girdled by the rub. I would say at the worst spot, about 1/3 of the bark around the trunk was rubbed off. I hope that means enough is left around the tree for it to continue to get nutrients, but I want to help it heal, in whatever way I can. I've read not to bandage it. Would fertilizer spikes be a good idea?
If anyone has any advice, I'd really appreciate it! I planted it to honor an animal companion who recently died, so I don't want this little tree to die on me too!
Thanks in advance for any help!

Not sure where you are, but if you are in the northern hemisphere, since it is almost November, it's not a good idea to give nitrogen to plants that will then shoot out new growth that might get damaged in the winter.

I've had just about everything happen to my fruit trees, and they are still doing well.  Just let the area dry over.   Don't wrap it in anything that could keep moisture near it and cause mold.   Just like a scab on your body, it needs to be dry and exposed to as much air as possible.  The tree will take care of itself if you keep the critters away.  Trees are tougher than you might expect.  

I was in an orchard recently that had 150 year old apple trees in it, and one of them was hollow at the base, yet it was 15 feet tall and covered with apples.   It's more about location, location, location.