Thanks for writing in to HCM & do hope we can help you.
From your history it is safe to presume that the fellatio was more than a month old. You say the symptoms of scratching are 15 days old.
From your description, it does appear that you may have contracted a fungal infection
of sorts..yes it may not be a 'classical' STD
but being transmitted through a sexual act, it does qualify to be an STD.
The white things could be non-specific particulate matter. Please go across to a dermatologist/venereologist near you & he will make you do a 2 glass urine test to help isolate if the problem is indeed some proteinaceous material & which part of the urethra
I think it is very possible that you may have aquired an infection from your ex-girl as you say the itching was noticed AFTER you had unprotected sex with her. Please check with her about symptoms.
It is best to do a routine urine test & the standard battery of tests for STD's & take this further.
Good Luck & Godspeed,,please do practice safe sex!
Dr Praveen Rodrigues MD