The bottom tip of my pennis is greyish, red and it gets itchy and there is white slime just below the tip of the pennis.
I pissed in the cup and they also did the swab test and took blood samples and I am CIRCUMCISED. I figured you want that info since most ask about it.
It doesn't sound like an STD. It DOES sound like thrush, a yeast infection.
You could try Monistat or something similar. Your doctor can prescribe an antifungal if necessary.