Difficulties with wearing a device? discussion

Could someone offer some guidance on devices digging into the skin and creating sores? We’ve been doing chastity intermittently since last September. The initial device was excellent, but looking back, the cage was a bit too long for him. He eventually stopped using it because the cage corroded even though we cleaned it regularly. This latest one is smaller and fits well overall, except for occasional pinching. More recently, however, it has triggered an area of thickened skin, almost like a lump, behind the lock that can get inflamed. Two weeks ago, when he removed it, there was bruising along his penile shaft; this skin split open creating a long cut and also produced a small blister. He didn’t notice it happening at all and was surprised to see it. Naturally, he’s been unchained while the tissue healed. We’ve been using baby oil on him and are wondering if that might have softened the skin excessively? He is wearing the biggest ring available, which I believe is 50mm, as he finds smaller rings difficult to put on; even this larger size can be a bit tight at times… We understand that occasional sores are normal, but this bruising and blister was quite severe! He really wants to get locked up again. The question is: should we stick with this cage or look for another one? I’ve attached a photo, any advice would be appreciated.

I took a good look at the picture. (Ooh, he has quite large testicles:) ). In my opinion, his cage looks a bit flimsy and not very high quality. I suspect there might be tiny rough patches on it that feel scratchy. They are small details and hard to spot, but if you file them down with some emery paper or similar, they will disappear. Alternatively, you could choose a cage made from slightly thicker material so it isn't as irritating.