Penis issue

Hello, I had low back surgery 2 months ago, and I was given antibiotics & steroid regimen for 2 weeks post-surgery.  Within 1 week of coming home, I noticed skin peeling on the tip and shaft of my penis.  I went to see my Urologist and he initially prescribed Nystatin/Triamincolone cream.  This did not help, in fact it seems to make the problem worse.  The Urologist has now prescribed Diflucan, he still believes it may be a yeast infection brought on the the steroids that were given to me post back surgery, but he is not certain.  In fact he came right out and told me that he does not know what it is, and neither does the partner in the practice.  The two Doctors have 50 plus years combined experience.  I am really concerned and it is quite uncomfortable for me, (itchy, painful).  Can you please help shed some light on this?  The plan for now is to see if the Diflucan can resolve this, but at this point the Doctor is not confident of the diagnosis, nor the treatment.  Please help.