Suggest Treatment For Penile Irritation

Hey. I went to a doctor because my penis hole, the bottom of the hole is irritated and hasn't healed in like 4 years. Every time I masturbate it aggravates it. The longest I've gone without masturbating is like 5 days, it didn't end up being long enough. I have made my penis like 1/3rd bigger from exercises and I don't know if that is the culprit. I went to the doctor to see if I had herpes. At first he thought I did and then he did a culture and he said I didn't not. What is the solution?