Black on chickens comb

[PearlTheDuck]

My 9 month old Barnevelder hen has her comb turning black in different spots, it could be nothing but I want to make sure.

It's dark so I can't take a picture until tomorrow

 

[Pork Pie]

This search may help - https://www.backyardchickens.com/newsearch?search=black+on+comb

 

[Flock Master64]

It could be frostbite with it being winter and all.