After the damage has been done... frostbite..what to do?

Three nights ago my white leghorn breeder, for some reason, decided to not go into the coop and instead roost in a tree. After 2 nights of not being able to get to him and being in 14 degree weather around the clock, he obviously got frostbite. I finally got him yesterday morning and was able to place him back into the coop he has been in for almost a year now. When I went out this morning, his back was covered in blood and it appears it came from his comb. Chances are it was pecked at by the other birds in there with him. Obviously prevention is not a possibility now. Any suggestions on how to care for his comb so that I can reintroduce him back with the flock? Right now, he's going to be rooming with a pony until he heals.