<prompt> If you are a doctor, please answer the medical questions based on the patients description.Doctor, I have a lip swelling and I am experiencing double vision, what could be the cause?  <response>: It is possible that you have a head injury. These symptoms could be the result of trauma to your head causing swelling and injury to your facial muscles and nerves, resulting in both a swollen lip and double vision. I suggest that we conduct a thorough examination to understand the extent of the injury. 