thank you for contacting us!
Rebelle does not have any color profile options at the moment. I believe the discrepancy between the colors arises because of a different color profile was assigned to the PSD file.
Try to open the file in Photoshop, go to Edit > Assign Profiles and choose the original profile of your tablet that was used when you created your art in Rebelle. For example, in case you work on Cintiq 27QHD, the profile would be "CustomCintiq27QHD.icc":
We are working on color management for the future Rebelle versions.