How to cure white skin patch?

Need more info...: Without visualizing your 'white skin patch' it is difficult to determine what it is exactly. My advice is to have your doctor examine it; and maybe even a dermatologist visit might be in order to diagnose it correctly.

Difficult...: Dark patches can often be helped with medicine such as topical steroids or hydroxyurea, which can decrease pigment in the area. Unfortunately, once pigment is gone, in most cases it will not come back. Conditions such as vitiligo can be particularly challenging. Most people find make-up or even tatooing are more effective than "medical" treatments.

Amino acids: White patch of skin is because the gut is stressed not secreting enough gut serotonin (serotonin is what body needs to make melanin the pigments) - this is caused due to gut not digesting proteins to break them into trytophan which is the precursor for serotonin. You can supplement with neuro-htp by biotics which supply niacin, tryptophan and helps with creation of melanin pigments.

Usually not curable: A new (not a birthmark), whiter skin patch can be due to partial or temporary loss of melanin pigment (such as after a rash or skin injury) and may regain some color over time; or due to a complete loss of melanin or melanocytes that make melanin... Creating a truly white patch. A dermatologist can try treating the patch. No extra vitamins, amino acids, or supplements can cure a truly white patch.