Don’t Undo the Last Stroke—Adjust It!
Rather than needing to undo your last stroke and try, try again, Adjust Last lets you tweak the last action. Use the Adjust Last slider to reduce or increase the intensity of a sculpting, painting or masking stroke. It can even be used to adjust an entire series of strokes from any marked point on the Undo History. To mark an undo point, move the undo slider at the top of the interface to the required position and then Ctrl+click on the marker.
Changing the slider value will raise or lower the last sculpted stroke, or fade polypaint. Negative values will push sculpted strokes inwards, similar to using Zsub.