It just wants some water.

That's what I figured, thanks!

Sorry, not sure I see much problem, just a tad wrinkly. Do you understand that these plants are tropical? Come from humid place & get a fair amount of rain?

That said, I'd suggest since you seem to have fast draining mix, you switch to plastic pots; it'll prevent the plant from drying out so fast.

Your concern abt over /under watering sound more like arid land succulent concerns than those of tropical cacti. These plants can take a big drink of water, as long as it's not done frequently.

I did know it was a tropical cactus and it gets more water than the rest of my collection. I guess I'm just (paranoid) worried about how long it's taking to bounce back, even though I know it's a cactus and therefore slow growing

So it still hasn’t really bounced back yet, most of the newest leaves are still wrinkled and soft, but not mushy. I moved the pot to a slightly sunnier location and noticed that it’s been putting out aerial roots from the main base as well as from the ends of the branches right before the soft leaves. I’m wondering if I should prune it back as far as the healthy leaves?