Hi, I have ,I`ve been told by Devon doctors this morning that I have an ulcer on my foreskin , been there about 3 days, very sore and itchy, the Doctor suggested that i may have an STD of some sort, but I do not think so as I have not had any different sexual partner for over 4 years now. They have prescribed me a caneston creanm and a antibiotc called FLU 500 mil (abbreviated), is this a suitable prescription?