making one normal higher then anther in a layer for a mesh

hello I am having a mental blank
I have a mesh witch has 2 layering on it, one a rust and the other a Paint, I am trying to make the paint layer seem higher then the rust layer, e.g there is a small shadow around the paint layer to give the look that it is higher, I have masked out the 2 layers so I want the shadow around the edge of the mask,
thanks for the help

Here’s some info on how to combine normal maps:

thanks for the help

had a look at it and it’s not really what I am after, its not a pre bake normal that I am trying to combine, paint layer is getting masked out by the mask texture, so what every mask texture I use the material will automatically have the shadow line to look like it higher then the rust layer, I could just do it in Substances printer but I don’t really what to have 20 or so more normal textures, I tryed crating “NormalFromHightmap” but that didn’t really work to well.

basically what I am after is in substance printer I have a “colour/ paint” layer ontop of my rust layer, I can set the Hight of the paint layer, E.g rust is 0.5 and the paint layer is 0.6(or something like that), this crates the affect of the paint layer being thicker and the rust has eating way at the paint, I have done it before I and I didn’t think it was overly complicated I just cant remember what I did.