Question Possible to photo edit light maps to "fix them in post"?

As I am working with a Revit (architecture 3D modeling software) to Unity pipeline, I have a lot of overlapping geometry, as this is how Revit works, resulting in a large amount of leaking light and artifacts in the light maps.

I was wondering if anyone has been successful in editing the .exr light maps in e.g. photoshop?

My approach have been similar to if I was editing a texture, but this is not quite possible with EXR files as their light data is stored in various channels in the image. As light is additive, the image is always super bright/white (notice that the image below's exposure is set to -7.1) and therefore the image becomes difficult to edit, no matter which software you use. Layers and masks are not really possible when working with light channels either.

Attached are examples of light leaks I would like to edit.

 

That is not correct, you can paint over EXR without affecting overall exposure etc, what is the problem exactly?

 

So because of the workflow from BIM model (Revit model) to Unity, we would like to paint over some of the light artifacts which appear (see the examples in the image in the original post).

How is your workflow for editing EXR?