There's a relatively new technique I've been reading about called 3D Transfers that can be applied really quickly, which makes a big difference on a student film's tight schedule, so I thought I'd give it a try. You sculpt the appliance, mold it, cast it, and apply it like a temporary tattoo before coloring it.
Here's how they turned out. Most of the veins are sculpted and painted on here. I think it's pretty successful, though there are still a few things I'd change, in retrospect.
A lot of detail is lost when these transfer appliances dry and shrink, so I'll have to make sure to exaggerate the sculpt more next time.