Often that vole/mouse damage initially appears to be more severe than it really is - we have had some of those chewed up lines as well, and have them again this year, but after raking away the dead grass you see (or will soon see) the new grass growing up. They don't appear to eat/kill the roots so the grass bounces back really quickly - hopefully yours will do the same.

I like to remember the year the winter mice ate my ornamental Blue Oat grass like right down to the ground and I was sure they had killed it dead. But lo and behold new growth jumped up out of those plants and they were nicer than they'd ever been.

Agree...today on the news they complained how much damage was done on golf courses and how many month it'll take to fix it.