The Healing Brush Tool retouches image using sampled pixels or pattern.
To retouch using sampled pixels:
In the Toolbox, select the Healing Brush Tool.
Set brush size and style.
On the Options bar, select the Sampled option.
Alt-click (click holding down [Alt] key) somewhere on your image to define a sampling point.
Paint with the Healing Brush Tool on the damaged area.
The Aligned gadget on the Options bar (not selected by default) forces the starting point to follow your cursor, even after you complete a stroke, while leaving it off starts the sample point back to its original location at the start of each stroke.
To retouch using a pattern:
On the Options bar, select the Pattern option.
Choose a pattern from the Pattern picker (movie).
Paint with the Healing Brush Tool on a damaged area.
Tip. Just in case you didn't know, the Healing Brush tool is also available in Photoshop Elements that is way cheaper version. And if you believe, Photoshop Elements lacks some other important feature, be sure to visit this page.