Yes. In Photoshop, place the two images on separate layers and use a blend mode like Difference or Subtract to compare them. That will show the relative per-pixel change between the original and the brightened version, making the altered brightness areas visible.

You can then use that result to build a mask—for example with Apply Image onto a layer mask. Starting from the original image, add an Exposure adjustment layer and use the generated mask to approximate the brighter version.

This works because the blend mode comparison reveals how each pixel differs between the two files. If the images are perfectly aligned and only brightness changed, the result should clearly isolate that adjustment.