discoloration on the tip

I seem to be getting some permanent discoloration around the opening on the tip of my penis. I notice that the color becomes a darker red/purple after I do my stretching exercises. Jelqs don’t seem to bother it, only stretches. Is this normal because I’ve only been doing PE for 3 months or is there something that I should be doing to counteract this redness/purple. I don,t feel any pain or soreness nor is the skin raised. Even after resting a day or two I still see this dark redness/purple. Your comments are appreciated. Thanks