something that annoys me a bit in some fanworks is when people forget about or brush past ushio's touch aversion. (not saying there are many fanworks that do this but in the few ive seen)
like for one, it's just nice to have someone touch averse in the cast (he's just like me fr).
on a character level, it is the direct manifestation of his trauma. ushio's trauma has changed him, so he has new skin. his trauma has impeded his ability to make connections, so the new skin is averse to touch. it serves not only as a metaphor for how he has been changed, but as a barometer of his emotional state, an indicator to the audience of how averse he is to forming relationships.
it's also interesting that ushio's coping mechanism of choice is reading yaoi. it comforts him to read about the sort of relationship he cannot have: the physically intimate kind.
we, as the audience, know that ushio is part of an otome game and is positively surrounded by cute guys (one of whom looks like his oshi cmon). like, of course he can have his cute, tropey yaoi relationship! he's got all of day2 to choose from! but of course, in his own head, he thinks this kind of connection is impossible, and so indulges in fantasy; reiou can be in love, even if he can't.
sorry if this is rambly and hard to read but yeah i think ushio's touch aversion is a really interesting and important part of his character.....!!! can't have the boy without the psychosomatic sensation of his skin lighting on fire am i right