Thank you for your question.
Hypopigmentation is mild loss of skin color. This usually results from an inflammatory process (pimple, eczema, fungal infection, medication application, etc) that leaves a slight whitish discoloration as it resolves. There are other causes of hypopigmentation including genetic conditions, malignant conditions, and certain diseases such as vitiligo.
In contrast, hyperpigmentation is where the skin turns darker. Depigmentation is complete loss of skin color, usually seen in vitiligo or chemical exposures.
Hope this helps!