"You went into Tedd's basement without even knowing how dynamic watch morphs work? Bloody tourists."
I believe this is going to be perfectly clear with Wednesday's comic (if not already clear today), but I may as well clarify: Nanase and Susan can use the watches again and try to get back to normal size, but it will effectively be a new enchantment with no guarantee of actually returning them to their default sizes. With non-dynamic morphs, you can usually just use the watch again to undo it.
I want to point something out Nanase's figure, but I'm not sure how to phrase it in the least awkward way. I mean, I really should just be direct about it, but this is me, and I've got some sort of mental block when it comes to this sort of thing, so...
The way her shirt is hanging might give the impression that's she has enhanced proportions somewhere around her chest region, but she doesn't. They're proportionately smaller than before the height morph, but the shirt is loose and fitted for a taller Nanase and... Yeah, I think you get the picture. I should draw tall Nanase in properly fitting clothes at some point.