There are a few reasons why your eraser tool might not be working in Photoshop. One reason could be that the eraser is not properly calibrated. If it is not calibrated, it may not be able to erase correctly. Another reason could be that the eraser is not properly connected to the computer. If it is not connected, it may not be able to erase correctly. Finally, there could be a problem with the software itself. If the software is outdated or if it has been tampered with, then it may not be able to erase correctly.