Since Last 20 Days I Have Observed Some White Colouring

Since last 20 days I have observed some white colouring on the pennis head, under the skin (I am uncircumcised). On first look it looks like snigma deposit but it is not, as I cleaned it thoroughly.
There is no pain or itching.
I have even consulted a urologist also but he said he has never seen any such thing.
He has prescribed to apply DIPSALIC-f to the affected area.
But I am confused because he told he has never seen such a thing.
It is also becoming a confidence and self-image issue if you are with a partner.
Kindly inform what to do.
Also I am not sure to consult a dermatologist or urologist.
Is it an infection, fungal growth, transmittable disease or a skin problem.
I had herpes six month back, is it somehow related to that.