Yes, the shower at the arrivals lounge is by far the best thing--for feeling as well as looking human. I never wear makeup anyway, so the lack thereof doesn't make me look any different--but I am always a bit horrified by the state of my hair (plastered to my head) after a red-eye. The shower really wakes up your skin, too.

I also change into pajamas (or something similar) for the duration of the flight. Not having to sleep in your clothes makes you feel better and look better when you put them back on at the end. This is easier done in J than in Y but it is possible if you make an effort.