You can remove your most recent paint stroke by immediately selecting Edit > Undo (hotkey: Ctrl + Z) after your paint stroke. You can erase paint from any active paint layer using the Paint Erase tool.

1. Click the Layers tab to display the Layers window, and set the layer display button at the top of the window to Paint.
2. In the Layers window, select the layer with paint you want to erase.
3. In the Paint Tools tray, select the Paint Erase tool.
4. Stroke across the paint that you want to erase.

   Paint is erased in the areas you stroke. You can adjust the Radius, Strength, and Falloff for the Paint Erase tool as necessary.