Hello, over the last year or so I have noticed darker spots (purplish) on the head of my penis. No pain, itching or oozing (in one picture the spots appear to be pustules but that is not the case). They do seem to be slowly spreading. The skin of the spots is slightly raised compared to the surrounding skin. I am guessing this is some sort of microbial issue but I haven't been able to find anything in my research. Thank you for your insight.