I noticed that we don’t call a person in red clothes “red person,” but we call a face with a red cream “red face,” eyes with red-colored lens “red eyes” or lips applied with a red lipstick “red lips.” Why is there the difference?
A person who is wearing red clothes is not actually colored red, but lips that have red lipstick on them are now actually colored red. We would only say a person was a "red person" if they were completely painted red. We don't say "a red X" if the X is merely covered with something else that is red.
Please be aware that "red person" or "red man" in American English can also be an offensive reference to an American Indian, so you should be extremely cautious about using the phrase.