Whether you use Adobe Photoshop painting tools with a mouse or a pressure-sensitive tablet, you're bound to have an error sooner or later. Fortunately, you can quickly repair that error with the History brush.

The History brush paints using the last snapshot or the saved file. Therefore, you can literally paint away your mistakes. To use this tool, simply choose the History brush from the toolbox, or you can press Y to choose the History brush. Next, choose the original image or a snapshot from the History palette. Then, begin painting away the errors.