Recovering Images with Camera Raw
Accidents happen. (Especially on that day). But usually, they're pretty fixable as long as your image is clear. Fixing over and under-exposed images is not nearly as impossible as it may seem. If you aren't shooting in RAW format, you should definitely start right now. This allows you to get a raw version of your image before your camera writes the lighting information onto the image file. From there, taking your image into Adobe Camera Raw becomes a breeze when correcting lighting in your images.
This is the out of camera, unedited image. Terrible right? My lighting kit decided not to respond that day, and left me with both an underexposed AND overexposed image at the same time. The whites are blown out and the shadows are all over the place. Luckily, the model's face wasn't too blown out.
This is what it looks like directly after adjusting the exposure in Camera Raw. Bringing down your highlights and upping your shadows can help to equalize your image and give you a better base to take into Photoshop and begin adjusting everything else. Overdoing it will give you that super HDR look that some love, some hate. So try to recreate a natural look when fixing images.
Additionally, playing around with ACR's color and luminance settings can be extremely helpful. If everything is well lit except for your model's skin, upping the orange/yellow luminance can usually bring your image back to life instead of letting the image go to waste.