If it isn’t a feather cyst, it may well be a squamous cell cancer of the skin. So hopefully, it is a feather cyst, since that isn’t fatal. I would probe it with a sterilized needle after cleaning the skin with a disinfectant looking for an ingrown feather or pus. Others have said that a skin...
It is hard to tell from the picture. Could you pull some of the feathers away from it and get another shot including the tip? The neck can be a common place for skin cancers, but it might be an ingrown feather cyst as well. I would make sure to watch to see if it gets larger.