How do I get rid of the question mark on my FaceTime

You might start by providing many more details:

• Where might this question mark appear?
• When might it appear?
• What model iPhone are you using?
• What version of iOS are you using?
• Does this question mark appear when you invoke FaceTime? If so:
  • Is it visible while you're in a conversation?
  • Does it appear when you attempt to place a FaceTime call?
  • Receive a call?
• Are you in a region that supports FaceTime?