Okay, I was circumsized at birth, but they left some skin - so there's some excess there.

That being said,

i just ejaculated - and let's just say I got really into it - and my penis has swollen. It starts off where the foreskin starts to swell, and kind of constricts around the head of the penis.

This has happened before - but it's the swelling usually dies down by now.
It's been maybe 20 minutes?

Is this just major chaffing, or is this bad?