Also, the model in Substance Painter won’t automatically update. If you updated your mesh in Blender, you can update the FBX file you’re using in Substance Painter by going to Edit > Project Configuration then from there select your mesh again. You need to select the same mesh, even if it’s in the exact same location and with the same name. This will force it to update then you can use the updated UVs. Note that if you did bake anything within Substance Painter you’ll need to redo that process.
