They can be caused by something as simple as excessive dryness or injury.

Other causes of lip lesions may include:

  • Allergic reaction
  • Cold sores (herpes simplex virus)
  • Yeast infection (thrush)
  • Stress
  • A vitamin deficiency
  • Weakend immune system

Lip lesions are usually not a medical emergency. However if your lesion is persistent or bothers you should see your GP in the first instance. If your lip lesion occurs along with other symptoms such as high fever, seek medical attention immediately.