hi, i have these red circles on my penis head, all the time, somedays i have more than others, alot of the time there is a build up of smug and it looks like white circles, but when i shower it goes back to just red spots, it started a while ago, a week or so after i had intercourse with my partner, i have had it checked out, but i am always told its not an STI/STD all results come back negative, any ideas?