I often have a little frostbite on the combs and wattles of my birds, the ambient humidity is just very high here.
Anyway.......
Frostbite on the comb points and wattle edges has always taken care of itself by itself. The frostbite areas just die and then fall off. As long as it is just the outer edges of the comb or wattles, I have never seen much swelling, or infection. The birds didn't seam too upset by it either. I just keep an eye on it, I don't do anything.
This winter I have leghorns for the first time (a fit of insanity on my part, stupid of me to have bought single comb leghorns)
With them, it looks like they have frostbite spots where the comb flops over. This is in the meaty part of the comb, not the edge, so I have been watching it. Dunno how this frostbite spot will heal, but there is definitely a greater chance of swelling and infection etc. since it is a dead spot surrounded by living tissue. Anyway, I am watching it now. I don't plan to do anything, and haven't done anything yet. I am just going to keep a very close eye on it, watching for infection.
I should add, that even though my chickens are pets, they are also fully livestock. If your chickens are highly valued pets, the extra time and money spent doctoring the wound to make sure there is no infection, would be worth it.