What is the best way to treat sore on penis?

Finding its cause, specifically if any chance for sexually transmitted diseases typically ruled out first as missing diagnosis and proper treatment may result in lifelong complications.

The best way is to not to try to treat it yourself. Only an exam and diagnosis, with a biopsy or a culture if needed by a doctor. The proper medications and treatment will then be given.

It depends on many things eg history of sexual exposure,duration, kind of sore etc. Best to have it checked by your doc/ urologist