It takes a lot of energy, spiritually speaking, and sort of.. rekindles extinguished elements. I hadn't given a lot of thought to visuals, but it would make sense if it generated vapor - the person being revived giving off mist or steam from sealing wounds, and from their mouth before they start to breathe again?

But then I'm watching an anime where that happens, so that's probably influencing my thoughts - call that optional, & go with whatever seems coolest.