What could cause penile redness if all tests are negative?

Hello doctor,

I had unprotected sex three months ago. I had all the tests except for herpes done, and all were negative. About every one to two weeks since the encounter, I have been getting red rashes and red small dots all over my glans penis and foreskin. They are not raised, they do not itch. They are maybe two seconds a day, and there is no discharge.

Although sometimes penis can produce an odor. The dots will disappear on their own, usually after three days, and can recur again after a week or two. There is nothing that seems to be indicative of herpes. Penis also seems very dry and wrinkly at times. All STDs (Sexually Transmitted Diseases) and HIV tests were negative.

Please advise.