Well now the title has got your attention, notice we are in the Photoshop Section. Here is a perfectly adequate portrait but it could do with a bit of polish.
First use the Curves and Levels techniques described earlier posts to get it as good as you can. Fix any major spots with the Clone stamp tool or healing Brush tool. Now duplicate the layer by dragging it to the new layer icon at the foot of the layers palette. This is next to the recycle bin icon, if you hover the mouse pointer on it, it says create new layer
Now you will have a second layer in the palette labeled Background Copy. Select the face with the magnetic lasso tool with a feather of 5 to 10 pixels. You don't have to be too accurate with this. Now select Filter..Blur..Gaussian Blur and blur it by around 30 pixels.
Drag this layer to the bottom onto the Add Layer Mask icon (gray rectangle with white circle, hover over it for the label). You will now have a layer mask thumbnail linked to your background copy in the layers palette (see next picture).
Make sure your background and foreground colour boxes are set to White and Black respectively and click on the Layer Mask thumbnail to make sure you are painting on that and not the background copy.
Press the B button to change to brushes and select a big soft brush. Change its opacity to around 30% on the menu bar. Paint over the face completely to reveal a smother image, I've just started this in the image below.
Now change to a very soft brush (40%) and set the size to around the same as the size of one eye. Change the opacity to 90-100% and paint in the eyes and mouth. You can also try painting in the outline of the face and jawline at around 70% opacity.
If the brightness/contrast now looks a bit off, adjust using curves. Click on the Background Copy thumbnail first before you forget otherwise a lot of the menu options are greyed out. It helps if you hide the marching ants by pressing CTRL+H to judge the effect properly. This will cause you many hours of amusement as you forget you still have a selection and nothing seems to work right.
That's about it really. If you want to tweak it more, copy to another layer to be safe. Now select the whites of the eyes with the magnetic lasso tool, (I assume you know how to select the little icons for new selection, add to selection, subtract from selection, and intersect with selection) select Image..Adjustments..Hue/Saturation and reduce the saturation to fade any redness etc. and boost the lightness slightly to brighten them. Do the same for the teeth.
You definitely need a new copy of the layer here because the Liquify filter is easy to get wrong. Once you create a new layer select Filter..Liquify
Down the left there is the magnifying glass to zoom in, hand tool to move around, a pucker tool, bloat tool, etc. but the first two are a pointy finger for warp tool and a brush for reconstruct. Select the warp tool and a large brush. Nudge the upper eyelids up to make the eyes wider. Nudge the jawline up on each side to soften the strong jawline and narrow the face. When you overdo it (not if) swap to the reconstruct tool and paint over to undo your changes. Don't overdo these changes as it stretches the pixels and becomes very obvious.
So finally, the finished image. The eyes have been slightly overdone to make the effect more obvious.