Is this a sign of lip cancer or an infection? (Photo)

Thank you for your question and your helpful photo.The area on your lower lip looks like something termed "Actinic Chelitis".  It is not possible to know for sure without examining you and this is by no means a formal diagnosis.  I'd encourage you to see a Facial Plastic Surgeon, Otolaryngologist - Head and Neck Surgeon or Dermatologist for a thorough history of the lesion, examination, and possibly a biopsy.  Hope this helps.