Ask HN: How do I make my own chemicals?

I want to make a substance that prevents calluses.

I'm not fussed about how it works. Perhaps it will be a spray that hardens or softens the hand so dead skin won't build up, perhaps it will be a paste that hardens, literally protecting the skin. It doesn't really matter, I just need some advice about how to start experimenting.

Beeswax, rosin, and pine tar have promising properties, how would I combine them with something like collagen or a synthetic polymer to get close to what I want? I've never done this before, and it seems unintuitive; blending A with B doesn't necessarily give A+B.

Any advice on how these things are done?