Advice and questions on making and fixing instruments
I've seen a couple used djembes which have the same flaw, and I wonder what people's experiences have been with this issue:

The skin rises up in a specific spot on the rim, for about 1.5", like a little hill or bump.
In both cases it's not the rim, it's the skin. (I know rims can be lumpy but these are warped skins)

Is this repairable? Can it be repaired without loosening the rope and/or removing the skin?
It's not the skin slipping (I don't think), it seems like it's just expanded in that spot, and risen upward.
It doesn't continue inward toward the center of the head, it's just along the rim.

My thoughts were:
Wet it and dry it with a hair dryer on low heat, to see if it can be shrunk back down.
Or, dampen the skin there, loosen the verts under it, and tug the skin to see if it can be pulled a bit snugger there.
Interesting. I would bet that this is a David Mühlemann djembe. It's exactly the material he uses - the cloth wrap, the rope of the loops, the style of shaving...

I am pretty sure that you have to replace the skin, cause this looks to me like the skin is ripped somewhere under this rim. Crank it up a bit and it will pop.
Thanks for the responses Djembefeeling and Michi, and for the warning about hidden skin rips, I had no idea, better not to learn the hard way, thanks very much.

Interesting to learn about the source and his style, thanks Djembefeeling.

That would make sense to explain the rise, but it doesn't appear that the skin has moved up from the rings to me. Looking closely at the skin under the bump near the rings, it seems level with the skin on either side (judging by stains and fleck patterns).
It occurs exactly where spine skin is, and is particularly dark, so I'm thinking somehow it expanded along the spine due to variation in density or composition there.

I still agree that it needs to be replaced. I imagine even if it could be tugged snug, it would find a way to buckle or warp again. I see why it's being sold.

On the other drum with this problem the bump is not on the spine line (doesn't have a visible spine line at all) so it very likely has ripped under the ring in the way you both mentioned.
Agreed the photo is of a djembe skin with a tear in it. We can see the wood. Is there another photo which is being spoken about.

There is a bump on the skin because there is a rip on the side. No tuning will fix that.

If there is a bump and no popped skin, it'd be uneven/unfinished tuning, or a loose skin that got wet and dryed and bumped up. I can't see any other reason why there'd be a bump. Uneven edge could do it i suppose but not when enough tension is applied.
Ohh, I see it now, thanks everyone. I wasn't seeing it because that doesn't match the wood color at all, and the color is much closer to the skin color. Here's the full view from the other side (bump in back)
djembe with bump sc.jpg
djembe with bump sc.jpg (67.62 KiB) Viewed 2005 times