Don't touch the comb if not necessary since it is very painful. I usually don't put anything on them, but iodine or plain neosporin just dabbed on gently would help to prevent infection. It will take several days to see how much damage is done. Sometimes it turns out not so bad, but any parts that remain black will become rounded off. Large combed roosters are very prone to this, and if you can make everything as dry as possible with good ventilation high up in the coop to help remove excessive moisture in the air, that is about all that you can do. If my temps get below 15 F I will put a heat lamp in my large coop, but those can be very dangerous. If you have a basement you can bring them inside when temps are very low, but ours only get down to single digits a couple of times this time of year.
