There are many possible causes of a red spot on your pet’s lip. These could include a traumatic lesion, a bacterial infection, a viral infection, the beginning of a cancerous condition, or potentially a condition called Eosinophilic Granuloma Complex which is an allergic reaction. Each of these conditions would be treated differently and you should not use over-the-counter medications for your pets without the direct advice of a veterinarian.
A physical examination is needed to help determine the cause of the sore. Commonly we will perform a test called “cytology”. This involves pressing a microscope slide against the lesion and then examining the cells under the microscope to help determine the cause and then the best treatment. You can call me with any questions at 813 885 4477. Dr. Peter Helmer