I need a diagnosis for something that looks like and ulcer or sore on my penis?

See a Doctor: See your doctor. This forum is not for diagnosis. Possible causes are herpes, syphilis, mrsa, chanchroid . Syphilis sores can go away on their own, but that doesn't mean your aren't infected. Syphilis can hibernate to later infect brain with a late form of the disease. Seek evaluation by a doctor asap. Most health departments are also able to evaluate, sometimes a reduced cost.