Sam, 5 months late, I find this post. How did I fall off the face of the earth again. You have so many amazing things to share!!!
You're the first person I thought of when I happened across this item of body piercing, metal, and meridians. You probably already know all about this, but to me, it was news, today:

The energetic effects of body piercings by Karen Kingston

It was fine to wear metal close to the skin in pre-industrial times but not such a good idea now.

Metal is a wonderful conductor of electricity, which is why it is used in wiring. However, metal anywhere on the body amplifies the amount of electromagnetic radiation (EMR) that is conducted through the tissues, and we are exposed these days to very increased levels of EMR from all the electrical equipment and devices that we use, as well as from ambient WiFi, radio signals, TV signals and radar.

It's a long article, and I'm eager to get outside, so I won't bother to block-quote all of this:

Body piercings are nearly always located in places that correlate to acupuncture points on the body’s meridians of energy. Acupuncturists use these points to insert fine needles for short periods of time to modify or unblock energies that are causing health problems, so having a permanent metal piercing there is certainly going to have an effect.

There have been a few documented cases of healing effects where a body piercing happens to have fortuitously been placed at the exact location where it stimulates an acupuncture point that corrects an imbalance. But I have yet to meet an experienced acupuncturist who recommends permanent body piercings.

They can play havoc with the flows of energies through meridians, especially those placed on or close to the centre line of the body, such as the navel, nose, tongue or chin. Even wearing a necklace with metal components or glasses that have a metal bridge across the nose can cause problems, and dental fillings certainly can.
..... Body piercing is not new. Ötzi, the oldest mummified human ever to be found, had pierced ears, and he lived over 5,000 years ago. Some Egyptian mummies have them too, and earrings were fashionable in ancient Roman times. Nose piercing is still practised in some Asian, African and Middle Eastern countries to this day.

But the wild variations we now see in the West mostly began in the hippy era of the 1960s and gained more popularity in the 1990s