3 weeks ago I noticed a redness on the right side of my penis rim about 1mm in size and it becomes dry and looks like cracked skin and peels like dry skin and there is no pain or soreness or blistering. I became alarmed and noticed that on the left side of my penis in the foreskin area right under the rim there is a pinkish rash that consists of 3-4 small bumps about 1mm in size and they are not really raised and do not hurt or itch though they are visible when I stretch out my penis. My penis head has been looking more dry and leathery as of recent as well. I am circumcised and my last sexual partner has been tested and says she is clean. I realized I had been accidentally masturbating with lotion that is used as sunscreen that had two chemicals in it and I had been using it since the beginning of June but stopped when I noticed the abnormalities on my penis. The areas I mentioned above also happen to be where I rub the most during masturbation. I have no pain during urination though I am worried because my penis still looks the same. From online research, it looks like Balanitis though can that only occur in uncircumcised men? Does this sound like an STI? Is there anything I can do to treat this at home? I appreciate any help.