skin care vs facial

skin care and facial both are nouns.

Word	Noun	Adjective	Verb	Adverb
skin care	Yes	No	No	No
facial	Yes	Yes	No	No

As nouns, facial is a hyponym of skin care; that is, facial is a word with a more specific, narrower meaning than skin care:

skin care: care for the skin
facial: care for the face that usually involves cleansing and massage and the application of cosmetic creams

skin care (noun)	facial (noun)
care for the skin	care for the face that usually involves cleansing and massage and the application of cosmetic creams
	cranial nerve that supplies facial muscles

skin care (adjective)	facial (adjective)
	of or concerning the face
	of or pertaining to the outside surface of an object