If your models cannot be in contact with latex you can use alternatives. Since Latex comes in many forms it's not entirely clear which form you're using but I assume you're mainly referring to latex prosthetics.
I think the most common alternative would be to use silicone. Silicone is a man-made alternative to the more natural latex, and it generally ...
This is washi tape. I often keep some on hand.
Ha ha, let’s test it on my hand.
It stays on for a while, but doesn’t bend like adhesive bandages. So, once the edge pops up, it is compromised. Sweat or moisture will not keep it on. Removing it once compromises it as well. It might stick for a while depending on movement.
The "go-to" material for a lot of people is something that is inexpensive and easy to make using gelatin and glycerin (and sometimes additional ingredients). It can be used directly or foamed. You can make a big batch of the material and it will keep for quite a while. To use it, you melt as much as you need (including recycles from previous use)...
I suggest a basic sunless Tanner foam ( lightest tan)dispensed mixed with some color agent that won't dye the skin permanently, like a children's bathtime paints.
Or, possibly use party streamers then either get wet to apply(an oil perhaps) or spray with body glitter for eye-catching gleam!
Here's an article on how it's made and the ingredients commonly used: https://luisafanzani.com/how-to-make-a-liquid-lipstick/. Getting all of the proportions right is part art, part science when starting from scratch. If it's dried out, it may not be just the solvent that's evaporated, in which case adding solvent wouldn't get it back to the same thing. ...