There could be several causes of these white spots. It would be best to consult your doctor with your parents to find out the cause in your case and plan the further management accordingly.
Some of the perceived causes are emotional stress, hereditary factors, worms, sunburns and physical illness. This skin condition can be aggravated due to diseases like hyperthyroidism, diabetes mellitus, pernicious anemia and Addison's disease.
Fungal infections of the human body are very common, and are often quite bothersome. One such example is a condition known as tinea versicolor, a superficial yeast infection that produces white spots on the skin that are difficult to remove.
You should talk to your doctor and rule out the above causes.
Let us know if you need any other information.