I’m not sure what you mean by which label? If you want readers to choose a hairstyle, you’d have to use a choice template. If you just want to change the hair to just one hairstyle without the readers choosing, the code is @CHARACTER changes hair into Hairstyle Name.
To use the hairbrush command, you need to add the hairbrush prop. But only INK has the prop, Limelight does not. A Complete List of Props and How to Use Them (Hidden Props Also!)