How can I remove the shadow from the photo in this case?

I would use frequency separation to separate the low frequency (tonal shades) from the the high frequency (texture detail) allowing retouching of each separately. To do that :

1. Make 2 duplicates of your image layer

Name the lower - "Low frequency"

Name the Higher - "High Frequency"

2. Select the Low frequency layer and use Filter Gaussian Blur (around 6.0)

3. Select the High frequency layer
Go to menu Image > Apply Image
Set the source layer to Low Frequency
Set the blending mode to Subtract
Set Scale to 2 *
Set offset to 128 *
Click OK

4. Change the blending mode of the high frequency layer to Linear Light

5. Now you can retouch each separately. I brushed colour onto the low frequency layer and then cloned out the shadow edge on the high frequency layer.

I hope that gets you started.

Dave




* Note - the above steps are for 8 bit/channel images. For 16 bit/channel step 3 changes slightly

3. Select the High frequency layer
Go to menu Image > Apply Image
Set the source layer to Low Frequency
Check "Invert" next to channel

Set the blending mode to Add
Set Scale to 2
Set Offset to 0
Click OK

Now carry on with step 4 above