Skeletons can sweat, though. Or something like that. Papyrus said so, Sans did it, but maybe there's something wrong with that 'cause of Judgement, or Sans only did it, or Gaster's actually not-too-bad-yet.

"Me too. Jus' tired. This time's not bad. For me." Frisk's actually taking care of their body. And there's a little bit less to worry about--although looking at Gaster resting there, that thought inspires a prickle of guilt.