Hello,
From the symptoms and picture the possibilities which need to be ruled out are balanitis ( due to fungal infection ) or Zoon’s balanitis which is a form of chronic inflammation of the glans penis and foreskin, which affects middle-aged to elderly men who have not been circumcised.
What you need to do is consult a dermatologist and get a KOH examination of the skin scrapings of the penis and a biopsy of small skin sample done. KOH examination of the area will clarify whether it is balanitis due to fungal infection or not.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.
I would recommend going back to your Dr to let him/her check you out. If there's no improvement then your Dr may prescribe another medication.