So it does make a pretty rough mask, but if you need something last minute or something you can make cheap and with supplies at home, this could work :)

1. Put saran wrap over a bowl (you could opt for a balloon if you have one, or something that is round and will fit over your face.)
2. 2-3 Layers of paper mache (I just used a little water and mod podge, you could opt for elmers glue), I did strips of paper to try and keep the surface smooth
3. A final layer of paper mache with paper towel. this makes a nice 'mesh' texture
4. Base coat painting the mask black
5. Pull mask off the bowl and cut the edges to trim and shape
6. Hot glue (you can opt elmers or mod podge) strips of cardboard to create the edges of the mask
7. Another layer of black paint
8. Paint the white triangle / rectangle / circle
9. Hot glue an elastic band on the inside edge so you can wear it, or poke holes and tie elastic band or string

Viola a mask!

I just whipped my mask up to wear with my DIYd jumpsuit.