I am not certain what you are asking, but here is the part of the American Kennel Club standards for the Shih Tzu that talks about pigmentation of the nose, eye rims and lips:


Pigmentation - Nose, lips, eye rims are black on all colors, except liver on liver pigmented dogs and blue on blue pigmented dogs.

American Kennel Club - Shih Tzu (http://www.akc.org/breeds/shih_tzu/index.cfm)