I can share my experience with Karma Gyurme for a first hand account.
In 2016 at Garchen Buddhist Institue Karma Gyurme Rinpoche offered a weekend of healing sessions. At the time had a really bad lower back issue that would flare up ofter. Injured it in aggressive yogic practices.
For the day I met him there were about 40 people waiting to have an audience. His attendant separated people into a two groups, mind issues, and physical issues.
The attendant asked each person the problem and if it was a physical one there were small marks made with a sharpie pen as to let Rinpoche know where the focus the healing.
When the group I was in went in he explained he was going to place a small ritual object on the spots we had pain. He passed around the object with was about the length of a small pinky finger. small ball like tip about the size of an eraser. Metal shaft the rest of the length and almost a half vajra like handle at the end.
We all felt it, inspected it etc. He said that passing it around created tendril with all the participants. He then placed the object under his tongue and said about two or three minutes of prayers and mantras, after which he called each person up one by one.
The first person goes up lifts there shirt and has some issue on there rib, the attendant kneels by them to translate what rinpoche says. He basically said "this is going to hurt." The person screamed in pain and was saying "ouch" "ow" etc and cried a bit. This went on for about ten people or so. Then my turn.
I went up lifted up my shirt to lower back he proceeded to place the object on five areas on my lower back almost in a cross like pattern, holding the object for about 10 seconds or so on each one. What I felt was this: Hot searing pain that went from warm to searing pretty quick. It was more like an energy current than like a screw drive left in a flame that gets hot an burn on contact. Like some kind of "voltage". Almost like an acupuncture needle but on a whole other level. It was painful, but since I knew it was painful I didn't touch ouch or cry or the like.
After the object was taken off and I sat down there was no pain, but instead it felt like menthol was rubbed all over my back.
There were other healings after me. He recharged the device via mantra after about half the people were seen. I even heard a women say she had a cancerous melanoma, he did his thing and said "you are fine now, go back to your doctor and then call my attendant and tell us what he says."
Another person I know who received the healing was touched by the object in the throat because he was going to have a surgery for an airway issue, im not quite sure what it was to be honest. However, he had a trip to Alaska, he came back and told me when he went through the metal detector at the airport it went off. When they pulled him aside to scan again it went off at his throat. He told them he was an electrician and the scar was from an accident with wiring so could be metal fragments. Lol. Pretty good one.
Anyway, rules where not to wash the burns or get water on them for two weeks, and no matter how bad they got do not touch them.
A lady broke those rules and washed, she ended up a day later in the hospital with a huge infection.
None the less, after two week I decided to try and do some Yantra Yoga I could not do before do to back and I was able to. It had been about a year since I could do certain poses. To this day I am good, a bit sore sometimes, but nothing like I was prior to healing.
p.s. I was running the center where he led the healing so was privy to more accounts like the lady with an issue etc.
There is more but tired of writing now.