You apparently are circumcised. You are describing your circumcision scar.
That darkish ring is your circumcision scar. It goes all of the way around the shaft of your penis. That is where your foreskin was cut off. It is not normal. It was surgically created. Intact, foreskinned penises do not have circumcision scars.
The skin on each side of the scar is different. The skin nearest your body is true skin but the skin nearest the head of the penis actually is dried mucosa.
When circumcised males restore their foreskin by non-surgical tissue expansion, the circumcision scar is hidden by the new foreskin.
My urethra is off center and my foreskin is tight (I'm pulling back little by little and finding progress). This means when I pee it comes out in a jet so I have to sit down. Problem?