You really need to rescan it. The image you posted is very blurry as is apparent because even the cracks are very blurry. Anyway, I used the technique in this post: http://www.retouchpro.com/forums/pho...tml#post135748
...to get rid of most of the cracks in a couple of minutes. It'll work 100% better once you rescan to get the image (and the cracks) in sharp focus. Then, using the principle that zekeode used, you mask out the facial areas where you want to do some manual work. In my case, the masks are also generated using a blurred and tone adjusted version of the image itself. Then I did a few minutes worth of reconstruction, but didn't put much time into it.