I read your problem with interest & concern.
I understand you have been sexually active & have checked for STD's & there is no STD & there are no symptoms of note except the itching & membrane formation.
It is very likely that this is a thrush
or fungal infection
most likely candidal.
Please do get to a dermatologist
on the ground near you for best results. Alternatively take a single 200mg tab of fluconazole
& observe the results. This may require a doctor's prescription though!
Avoid shaving against the grain but in my opinion, unlikely related to this issue.
Cheers & good luck!
Dr Praveen Rodrigues MD