Procedurally created Normal from Float Heightmap within an Unreal material?

Hi guys,

Trying to do something similar to that ‘Adam’ film from Unity wherein a character has a flowing normal map in place of their eyes. One method I thought of to be able to do this is to use grayscale maps to isolate the parts of the mesh that I want to place this effect on, and then multiply some panning texture samples to get the effect I want. However, the NormalfromHeightmap node doesn’t work with float values, as I was disappointed to find after crafting the effect in all the nodes beforehand.

What’s a good solution? I don’t need to create the normal outside of Unreal, I need a way to append procedurally created normal information into an existing normal map created in substance painter.