Not everyone has a mild winter, mine have some frostbite on their combs, even the ones who had it in past years, so I'm familiar with frostbite.He looks to be about a year old based on spurs. Any frostbite from last year would show shortened, almost amputated, appearing tips of the comb. Usually it is on the tips and can appear as blistering shortly after. With the relatively mild winter we've had, I'd lean to pox.
Battle scars would also appear more linear and not in the 'meat' of the comb, usually something easier to claw or bite. Also battle scars will also occasionally have some marking on the wattles from beak bites.