As some have said, they are likely using CGI to enhance the look.
Reminds me of 2010's a Nightmare on Elm Street
They used makeup but, to enhance the burn wounds, used cgi to enchance it and they put tracking dots over the makeup, similar to Malekith in this.
As far the them possible changing the color of the makeup in post.. its kinda unlikely but it has been done before.
For Dragonball Evolution, the makeup for piccolo wasn't green, or at least, as green as fans would have liked.
Point here is, the went and retouched in post and made him much greener.
while its unlikely, they could do the same thing here.