I think that is just simply frostbite.
I got to say though, I don't think I have ever taken the time to smell frostbit combs.
It looks like it will heal perfectly on its own. I wouldn't do anything to it.
As whatever parts decide to fall off, there is usually some blood or a little oozing fluid, but I have never had a problem with frostbit comb edges. (toes are a completely different story)