genital and anal itching , but no rash or sores after unprotected extramarital sex

[svensky]

1 day after unprotected sex, my scrotum, glans and anus had a dramatically noticeable increase in itching that has continued for three more days (including today).  Experiencing occasional shooting pain on tip of penis. No sores, blisters or rash, but enough discomfort to awaken me each night multiple times.   While I understand this could psychological due to guilt from an extramarital encounter with a friend, could you rank order the probable causes and what can and should be done.

Days prior to the sexual encounter, was diagnosed as a very borderline diabetic (57 years old) and to what degree can the higher sugar level be feeding skin fungus that causes itching in genitals and anus?

[Casually_Observant]

You may have picked up a yeast infection from your sexual partner.  Or, worse, an STD. If it is a yeast infection, a simple course of over the counter Monistat 7 may get rid of it, but if you try this and your symptoms subside, you may think everything is OK.  But, some STDs have initial symptoms that abate, and you think you are fine, but then they flare up later.  

Meanwhile, you have infected everyone you have slept with (unprotected) since.  Common sense dictates a visit to your doctor for an exam, ASAP.  Don't worry about being embarrassed. Better to have it addressed and cured right away than to suffer any more days of this!

I certainly hope you DO NOT EXPOSE your spouse or anyone else to your nether regions until you get this treated and cured.  Hard lesson has been learned here!   Use condoms before you have sex, ESPECIALLY WITH A NEW PARTNER and certainly so you do not cause your marriage partner this kind of grief!  Good luck....

[Caryopteris]

I would treat the skin with Lotrimin cream and see if it improves.  If it seems to help, follow instructions on the tube and finish a course.  Follow your low-carb diet. Add a probiotic supplement.