As others have said that is very, very mild and you should just leave it alone. Don't touch it - your biggest concerns are it may be a bit sore for the chicken so touching is a bad idea.
I had one hen who got some frostbite on a couple of tips. Worse than what you are showing but still not severe. It took a couple of months before it looked normal (I think she lost one tip but it is honestly hard to tell now).
The only thing I notice a year later is the one tip that was worst effected has a tendency to turn a little blue in the cold - no more frostbite but it is like it is a bit more sensitive having been damaged once.
The frostbite was due to inadequate ventilation in their first coop so best thing is to focus on prevention by making sure you have good ventilation in the coop.
