Yeah, wrong text with that picture. This is a wild-ass guess, but the knobs on the woman's back may be small glasses (of the drinking variety). Something I learned from an acupuncturist: you set a cotton ball on fire and toss it into a shot glass, then put the mouth of the shotglass against the skin on the back. The removal of oxygen causes the flame to go out, and creates a vacuum that pulls the skin into the glass. Allegedly this draws toxins from the skin (or even, I have heard claimed, the lung themselves.) I dunno if it works, but it'll give you an impressive and interesting hickey.

Anyhow, if this is a bathhouse thingie, maybe it did double duty (like a barber-surgeon) as a spa - we're talking DEEP pore-cleansing.