What Causes Dry Patch On Skin And Blisters On My Penis?

i am a 26 year old male and i have had a white dry patch of skin on the ring of my penis up to the opening for a long time, it also has small white like pimple/bumps under the skin that are about 1mm so they arent very big but are very dry, it doesnt itch at all and it doesnt bother me but ive noticed that its gotten bigger, ive had the same partner for 9 years and neither of us have ever had any STD's so i am alittle worried as to what this might be.