It looks like what the practitioner (I can't bring myself to use the word doctor) is doing here is a variation of
cupping. I hadn't seen cupping associated with bloodletting, though. (I'm reminded of Steve Martin on Saturday Night Live doing the Medieval Barber Surgeon sketch ... "We'll have to bleed him!")
The glass jars are affixed to the skin by means of a vacuum formed by heating the tops of the jars. The things people will pay for ...
That being said, however, our friend the leech is getting a second try in the medical world ... they are being used to assist in restoring circulation following limb reattachment surgeries.
Other seemingly icky treatments include using maggots to debride infected wounds (they work cheaper than even medical residents).