Bark damage may shorten the life of the plant. If it were to girdle the trunk, it would kill the plant, but it doesn't sound like that.

Current advice from extension agents is:

"Removal of even a vertical strip of bark less than one-fourth the circumference of the plant will harm the plant, but not kill the plant. When the patch of bark is one-half or greater, the chances of plant death increase. Complete girdling (the bark removed from a band completely encircling the plant) will certainly kill the plant."
[New Mexico State University]

"Carefully trim away all loose bark back to the area where it is solidly attached. Do not cut too deeply into the wood of the plant. This cutting of the bark is referred to as a bark tracing. If possible, all bark wounds should be cut into an elliptical shape, being careful to keep the trace as narrow as possible. This may be difficult on large areas. However, trimming the bark in this manner will encourage rapid healing with minimal wood decay."
[Texas A&M University]

"All wounds larger than 1 1/2 to 2 inches in diameter can be coated with wound dressing or pruning paint. Recent research has shown that dressings and paints probably do not increase the rate of healing. However, they may prevent drying out and provide some cosmetic effect. Several commercial materials are available or a couple of coats of orange shellac suffice. Areas of torn bark where tracings have been made can be treated in this manner."
[Texas A&M University]

I prefer grafting wax to protect damaged areas. It obviously works on grafts and won't hurt on bark damage.

Here is a link that might be useful: Throwbridge's Grafting Wax