Sealing leather against skin/sweat

[Sprocket]

I've been task with making a Dread Pirate mask that will be made from 3-4 veg tan - the color needs to be black and it will be worn against the skin.

What products would you recommend to seal the back side of the mask in contact with the skin?

I burnished the flesh side of my prototype with black Tokonole - turns out the color bleeds with water...  At least the surface is smooth.  The plan is to dye the front black and then finish the whole thing with "something" to seal against sweat and prevent color from leaching into the skin.  I'm just sort not quite sure exactly what to use.

Thanks for looking and responding.

[TomE]

I use this adhesive sealer on some projects to recreate the moss-back (pasted back) on bridle leather after splitting the thickness.  Work it into the leather with a glass slicker to paste the fibers together.  Seems to wear fairly well on horse tack.   https://campbell-randall.com/product/sup-bt639-g-leather-finish-for-sealing-flesh-side-moss-back-suede-1-gal

Since you've already applied burnishing gum maybe a surface finish would be better for correcting this project.  Lincoln Stain Wax in neutral (no stain) will provide some shine and might serve as a barrier to contain the black Tokonole.  It's a high end shoe polish and it smells nice! 

[Sprocket]

Wax - Hmm - would bees wax serve?  Thinking out loud as I have some on hand for other uses.

Thanks for the response

[fredk]

Mix the bees' wax with some carnauba wax. That takes away the 'stickiness' of the bees' wax. Carnauba  wax is safe to use