Oh, I suppose this is a hag lair and hags love both bargains and curses. Perhaps it's a trap.
You use the full recovery spa and get fully recovered, but by doing so you've accepted hidden (perception, insight, or some type of intelligence check?) terms and conditions to allow the hag to sap your life force. During the combat with the hag, she can do [something bad idk] to any characters that benefited from the recovery area.
