Write a sentence that uses the word paleness as a noun, referring to a person's skin. For instance; John's paleness showed he hadn't left the house in weeks.
Replace "paleness" with "pallor" in your sentence. John's pallor showed he hadn't been out of the house in weeks.
Re-read your sentence and ensure that it reads smoothly and still makes sense. Pallor can sound a bit stilted and formal in some cases.