Face tanning process time and sweat and friction

My question is pretty specific!

I work in a steel mill and would love to figure out how to keep my face tan. Since I’m on tret, I’d prefer to use a gradual face spray every other day or as needed.

My question is: how long does it need to sit on the face undisturbed for it to process? Will sweating affect this? How about having a hard hat sit on my brow? How long should I let the spray process before working?

Thanks for any and all advice you can give!