Could A Brown Patch Under The Head Of Penis Be A Matter Of Concern?

Hi, I noticed a small patch under the head of my penis, inside the loose skin. It was white earlier and small. Now this has enlarged and has a dark brown color with white border. I researched a lot on the website for this condition but found none. So far, I have not felt any pain in the area not was it itchy. Initially noticed this as i was cleaning cheese like formation under the head of penis. I have not had sex too. Is this something serious? What do I need to do? Please advice on this. A bit worried.