+++Help! +++ How to Edit normal map from a baked 3D geometry

#1

I have a character sculpted highpoly in Zbrush and Retopologized in maya and did baking and texturing in substance painter.
Now the question is I need to modify the model. what should I do ?
If I modify it in Zbrush highpoly and then lowpoly in maya the resault is that I have to rebake it in substance painter for normal map.
Because I have already painted it by hand in substance painter when I rebake the model in substance painter all my brush strokes are in wrong positions :sweat:
14
As shown in the rendering I need to make this region smoother