I have red spot on the head of my penis and pain in the urinary tract opening. Why?

Hi doctor,

I am 45-year-old male. I am 70 inches by height and 165 pounds by weight. I had unprotected sex, oral, and rimming. After few months, I called the doctor and explained the problem over the phone, then started on two cures antibiotic tablets when I thought it was cystitis. After that, I got an appointment with my doctor, and he did a test on my penis head and found few colonies of two types of bacteria in the sample they are, Hemolytic streptococci B and probable enterobacteria. He prescribed Miconazole nitrate for four weeks and Metronidazole antibiotic cream. When my pain had become very bad, and sometimes there was a clear discharge, I contacted the dermatologists. My dermatologist had blood and urine samples taken for diseases with a negative result. He asked me to stop taking Metronidazole, which also partly helped with the pain. Now I do not have pain all day, but pain appears at regular intervals. Due to still severe pain, I contacted the dermatologists again and had a meeting with her. She saw no signs of bacteria. I saw my own doctor the next month to do inoculation as there was still a lot of pain and told if bacteria are gone. It shows negatively on bacteria, only good bacteria.

The next month there was a discharge from the penis and general discomfort. There was a pain when the tip of the glans or mucous membrane touches my underpants. There is redness around the urinary tract opening as if it is irritated, and the skin is slightly swollen in some places. Today I do not have pain when the glans touch my underpants, and my skin is not sore as it was before. After some time, when the red skin around the urethral opening has been touched after contact with the underpants, it slowly starts to irritate, and the pain slowly comes. And when I pee, it also starts with the pain as if a wound is open. I get also pain in the urinary tract opening or the swollen area as soon as I sit down on a flat seat. It takes a short time from the time I sit down until the pain begins. The problem has been there for almost a year. Is the skin damaged? Why is it red? What do you think I am doing wrong?