This would be a monster task and would likely not look like this baby. I think your best bet would be to use another photo of the child's face, make a rough selection, transform it down to the approximate right size and angle (you'll probably need to use the warp function and if you have CS5 or 6, puppet warp) fit it to teh face as close as possible, apply a layer mask, brush the edges to "melt" into the face, and use the transform tool again as needed. You can go back and forth with paint on the layer mask, black to make transparent and see the pacifier that needs covering and how to line up the nose, chin, etc., and use the white to fade your "repair" piece in. Use relatively low opacities for blending.