Thanks for the feedback! I've got a fix waiting on the jam to finish that should address the dialog boxes. Just have to wait forever to be allowed to update it, lol.
As for the "ink stain" I assume you mean the little circles that trail the blotches? That's a very similar effect to a fog of war effect from an RTS. The way I've got it is that there's two pictures layered on each other. Blotches get trailed by little distorted circle sprites that a shader uses to basically erases that circle from the parchment layer, just like a fog of war you're probably used to in other games, but parchment colored instead of grey or black. However, that same distorted circle get's drawn temporarily on top of the full colored town map, with a shader that darkens it a little, gives it a darker outer edge to mimic watercolor, then fades away. The rogues basically just do an undo of that, reapplying the fog of war effect.
Thanks for playing!