Is it a hair ring?

Alright, so Pip was cleaning himself for the second time in the 4 weeks that I've had him. Or that I've seen anyways. It's about 2 AM for me at the moment, and this happened hours earlier. But as he was grooming himself it looked like his penis was red and had what I can only describe as a "knot" at the top. I don't mean a knot of hair either. I plan on taking him into the vet later today to check for a hair ring because I'm not entirely sure how to and he won't hold still for me to try and examine him. Not to mention he hasn't really been here THAT long, so I don't want to stress him out. He hasn't been frequenting that area much, I've been keeping an eye on him. He's eating and drinking fine, sleeping hasn't changed. But I was also told that Chins tend to not show a sign that anything is bothering them unless it's extremely severe. Was Pip just enjoying himself or does this sound like there's a hair ring that needs to be removed? He's between 6-8 months old. He's the only chin I have, so there's not a chance that breeding could cause the issue. I just want a little advice. I don't have a problem taking him to the vet. :D But when I saw him grooming himself I didn't see any hairs, but I know that doesn't necessarily mean that there isn't something very thin there. He doesn't seem uncomfortable. When I had Charlie some years ago, I never heard of hair ring and he never groomed himself to where I'd see it. So any tips on how to get little Pip to hold still so that I can check as well would be great! :)