>>5390013>>5390011Thanks, anons!
It was a multi-step process, but overall relatively easy. Here's a tutorial for ya candy!
I started by clipping off every damaged part of the mask with some Swiss army knife scissors (no particular reason, they were just on-hand, but I'd recommend them on account of how precise and common they are).
Because the cuts were asymmetrical, I spent a while just looking at the mask and editing profile and front-on pics in GIMP, trying to figure out how I could cut the remainder to look nice and have some symmetry.
Next I took a sharpie, marked the cuts I wanted to make on the mask and got to trimming.
Once satisfied with the cuts, I smoothed everything out with my dremel tool's grinding burr and sanding barrels of varying grit.
The last step was to clean up the remaining sharpie with some rubbing alcohol and a final rubdown with some nail polish remover to remove the "scraggly bits."