Suggest Treatment For Dark Patches Appearing On The Penis

hi, my penis tip has gotten some darker red patches on it, as well as very strong smell of urine, especially when i am going to the toilet, and urine is darker, but no itching or soreness, and no STDs as my partner and i have been tested, we have sex about 5 times a week without a condom, but always shower after or the day after if that has anything to do with it. please help!