How exactly do I edit a normal map correctly so it reflects the changes when I put it into my poiyomi shader? I have never done it before and assumed it wasn't that complicated. 

I opened it in photoshop and edited out the part of the normal I no longer wanted (made it blue/purple with no bumps) but when I save this and add it to my shader (replacing the original normal map) it just...does nothing? it takes off the entire normal map from my avatar, the only one that seems to work is the original un edited normal map and idk why