Massive skin discolorations are rare, if they happen at all. There are some reports that stress and anxiety can cause liver dysfunction, which may lead to jaundice (a yellowing of the skin), but most skin problems are going to be fairly minor and not necessarily mean that there is any type of underlying skin problem.

Symptom of skin color changes
Changes to skin coloration can indicate various medical conditions. Whitening can occur due to infections or to loss of pigmentation such as in vitiligo. Paleness can indicate a variety of severe infections, either local or to the entire body. Redness can indicate a variety of possibilities including local skin inflammations. Blueness can indicate cyanosis such as from lack of circulation and can be very serious. Dark skin, darkening of the skin, or "hyperpigmentation" can occur due to various medical conditions. Any changes to skin coloration need medical investigation.

Causes of skin color changes
Possible causes of symptom: Skin color changes: The following medical conditions are some of the possible causes of Skin color changes as a symptom. There are likely to be other possible causes, so ask your doctor about your symptoms.

Causes of skin whitening:
Vitiligo
Pallor

Cause of blue skin:
Cyanosis 

Causes of yellow skin:
Jaundice - causes yellow skin
Carotenemia - causes orange skin

Causes of skin darkening:
Hyperpigementation