And all said and done, forums do fall short of accurate diagnosis, nothing like patient being examined by doctor, these only give you a pointer, and a plausible, possible diagnosis.
The art of dermatologic diagnosis is primarily visual, indeed supplemented by investigations.
For example Lichen planus(LP) is violaceous, flat topped, more often on the penis, than the scrotal area.
Do consult your doc always.
It could be Lichen Planus - there are so many different skin disorders, that it is not always easy to get the correct diagnosis.
A skin swab would show if there is any fungal or bacterial problem.
But in any event it is important not to use soaps, bath or shower gels. These things dry out and irritate the skin even more.
Don't neglect this and make an urgent appointment to see your doctor.
I can also see a small area of broken skin too.
Don't use ordinary soaps. Only use non perfumed soaps, soaps that have the same pH level as our skin and baby washes should be fine too.
You can purchase emollients from the pharmacy without a prescription that you can use as a substitute for soap. These are also moisturising.
Only wear cotton underpants.
Make an urgent appointment to see your doctor.
Let me know how you get on.