The type of dark spot that is left behind after a pimple is gone is called post inflammation hyperpigmentation. It occurs after an inflammation like acne heals, but can also result from any injury to the surface of the skin.  The skin responds to inflammation on its surface by generating new skin cells to heal the damaged skin. Dark spots occur when the cells that are sent to restore the surface of your skin contain too much melanin. 

If there ever is a skincare hero award, Vitamin C should probably get it. This well researched ingredient offers amazing skin benefits that are well documented. In terms of its importance, it ranks right after sunscreen in preventing premature aging. 

The terms lightening, whitening and bleaching are often used interchangeably. Skin bleaching is a term that was more popular in the 80's than it is today, and is essentially the same as skin whitening. The difference between skin lightening and whitening is largely based on the degree/severity with which melanin production is reduced.