Frostbite?

[HowIsItDone]

Agrees, do not touch it, before or after.
It will heal but it can take months for it to fully recover.
Here's a pictorial story of the progress:
https://www.backyardchickens.com/articles/frostbite-in-sw-michigan.74597/

Aart for the informational win every time.
You're a gem.