Pink skin was an Andorian slang term for Humans, in reference to the 'pink' skin color of some of the first Humans that they had encountered. It can be a deragatory, neutral, even polite phrase, depending on the context in which it is used.
The phrase was used many times by Shran and once by his daughter, Talla. (ENT: "The Andorian Incident", "Shadows of P'Jem", "Cease Fire", "Proving Ground", "Zero Hour", "Babel One," "United", "The Aenar", "These Are the Voyages...")