The following code always prints the first message, not the text following [otherwise].
Instead of examining yourself, say “[if we have not examined yourself]As good-looking as ever.[otherwise]Still as good-looking as ever.[end if]”
My intention is to have the word ‘still’ show up always after the first time the hero examines themselves.
However, the word ‘still’ never shows up, no matter how many times I examine myself in-game.
What am I doing wrong?
It’s because you’re using an Instead rule. That means that as far as Inform knows, the examining action never actually happens, so it never marks the yourself object as examined. This would be the most natural way of doing it:
The description of yourself is "[if we have examined yourself]Still as[otherwise]As[end if] good-looking as ever."