this was all covered already but i wanted to say hi and stuff and also just add more input :33
if you're using ben nye i have to say that powder and final seal will be your holy homestuck cosplay deities. i'm assuming you're using hanyaan's tutorial so you probably know that already.
what happened at otakon was that it did rub off my hands a little. keep your makeup with you in a bag or something, for touchups. if it comes off anywhere just touch up in the bathroom whenever. o u o
it probably won't come off though, for my nepeta cosplay i applied it once at 7:30 in the morning and it did not budge at all
until i had to scrub it off at 1AM!
nails: paint them yellow before the gray, probably the night before the con so you know it'll be dry in time. normal nail polish! and remember to apply it in a lot of thin coats as opposed to one super thick coat; it would smear less.
man yellow contacts are totally optional. especially the sclera contacts that cover your whole eye oh my god those things are like $250 per lens, it's definitely fine if you don't have them don't even worry!
for karkat if you really really want all the pointy teeth there are two options: using tooth black to black out the corners of each tooth so it looks like a point instead of a normal square tooth shape, i've seen people do that and it looks pretty good. a second option is to buy a full-mouth thing like this
, which i've also seen used, but these are by far much more pricy.
of the two i'd suggest tooth black because it looks good and it's much cheaper, but again, it's totally optional; you can choose one or the other or neither and your cosplay will still look great! o u o
ears: yeah just cover them with some more of the same makeup :3