Red line on balls

After about a week of wear the skin on my balls under where the ring sits tends to turn red, like a visible line where the ring touches the skin.

Is this normal? There's no chafing/burning feeling and I can sleep without any trouble. I just get some low grade itching and occasional slight pinching in that area on my balls.

Is this maybe due to the ball gap being too small, and I need to try the Curved to see if that works better?

Wearing a Cobra E Standard with size 3 Standard ring.