I thought I knew all about this, but my 6 yr old son asked me a question this morning when he was getting out of the shower. He is partially retractable and he pulled it back as far as it would go (to where about 1/3 of the glans was visible) and asked if it was supposed to be red there. I thought he meant the glans and said yes and told him the name of it. But he said that he meant the retracted skin that was stretched over the glans (the inner foreskin?). I noticed that it was more red than the surrounding skin he said it didn't usually look like that, but that it didn't hurt either. We talked a little bit more about retraction and I told him I'd see what I could find out.
So, is that redness of the inner foreskin a part of the retraction process? That's my best guess, since he doesn't have any itchiness or anything.