Chemical bleaching can lead to serious skin and health conditions which include: permanent skin bleaching, thinning of skin, uneven color loss, leading to a blotchy appearance, redness and intense irritation, dark grey, white spots, skin cancer, and acne. The possible side effects of using products that contain hydroquinone, corticosteroids or mercury include: skin becoming darker or too light, thinning or showing visible blood vessels; scarring; kidney, liver or nerve damage.