Faces is one of my favorite Lewis tales. Every time I read it, I find deeper meaning.
Lewis not only considered it his greatest work, but his mystical autobiography. It's a stunning masterpiece that contrasts the limitations of natural love, especially when it comes into contact with divine love. He saw all of our souls - particularly his - as being so caught up with natural love that we close ourselves off from divine love. We'll take the best we can seize from what we see with our natural eyes, and so focus on that that we cannot see the greater good being offered us.
.....Had Orual trusted Psyche, her eyes may have been opened. But that same trust would have meant losing Psyche, so she quickly buried it beneath condescension, fear, and hatred.
That explains it better. I had no idea it was sort of an autobiography. I was reading this morning, after reading your post PotW, when Redival was punished to spend her time with the tree, Fox,Orual, and Psyche.
"Thus all comfort we all three had was destroyed when Redival joined us."
You said Orual and Psyche were both a picture of Lewis. At an early age Lewis was said to have read all sorts of book, including Paradise Lost at age nine(!). This love of knowledge (possibly the Fox?A very good picture of logic) he carried throughout his life. Eventually he became atheistic while at the same time jeopardized it by falling in love with christian writers like George MacDonald and Chesterton. ('I didn't know what I was letting myself in for. A young man who wishes to remain atheist cannot be too careful of his reading. There are traps everywhere'. -Surprised by joy)
His logic said there could be no God. (The Fox: "Those gods, the gods you are always thinking about, are all folly and lies of poets. We have discussed this a hundred times.") Orual was reluctant in believing Psyche the same way Lewis was so reluctant to succumb to what his authors and even colleagues believed in. He felt a betrayal, it seems, towards the world and fought and denied bitterly, trying not 'to be taken in'. But everything around him pointed to a loving God. Maybe like Psyche's Palace?
It was years he fought like this against the rising tide of authors he loved and colleagues he respected, living two separate lives, one in imagination and the other logical. It was after his conversion that he learned to combine them I think.Why couldn't he have the Psyche without the cupid, or the romance and logic of the authors without their God? Is it the struggle between his view: 'The world is a bitter place so we must accept it as so; Pretending it was not so would only lead to despair or madness' and coming to terms with his romantic side like that between Orual and Psyche's love for cupid?
Also their father reminds me of the cruel schools Lewis was sent to over his childhood. Perhaps its only the unjustness of the world altogether, or maybe something else.
Anyway, when I threaded this I was surprised the C.S.Lewis section only had three threads. That's when I realized I had the thread viewer on 'Last month' only.

After broadening the time span, I quickly found that there's already a thread about this book. Sorry for posting another.
Also the veil seems like another puzzling question entirely. It does seem like there's something important there. Let me know if you find anything in your research.