Bud is dark not green

So i have a friend who just harvested and his bud is like a dark color its not green the strain is “viscaria” Is there anything we could do to bring the color green back ? or thats just the end of it

Do you have a picture? Are you talking like bud rot?

Have you got a pic ?
Some genetics will show purpling or darkening naturally. Some with colder temps.
But the pics would help a lot in showing what’s going on.