This particular part:
spoilers:end of spoilers
"Facial expressions and body language are just how people communicate, but they don't mean the same thing here as I'm used to."
Makes it sound like these 3 species are now just expressive beings without actually feeling anything, basically instinctually it's like their bodies knows how they should react physically and maybe even vocally but they emotionally feel nothing when they do so, which I think explains the "they don't mean the same thing here as I'm used to" b/c if these 3 species weren't physically expressive that last bit in the quote wouldn't make sense; instead Jo would probably have said "Facial expressions and body language are just how people communicate, except here, aside from me, no one here feels a thing."
Also, idk, maybe the medicine just doesn't work that well ...or maybe there's a twist to this.