My skin was soo white before three years and my skin suddenly has became nearly black and i have a sensitive skin please tell me what to do?

Doctor can evaluate: Skin symptoms are difficult to describe in words. A primary care doctor or a dermatologist can examine a hyperpigmented (darker) area of skin to see what it might be. Some parts of the body are naturally darker than the rest of the body, in everyone. However, certain darkening patterns are not normal and may be due to hormonal disorders.

See: You should see your dermatologist for treatment and evaluation. This way you can find out the cause for this problem and receive the correct treatment.