Hii dear , you can apply lemon once in month( massage ur face with  lemon skin ),make a smooth mask of besan and milk,can avoid soap or face wash instead of that use multani mitti to wash ur face (gently),go for gud faical also and drink water lot may this help u ..

take care

Dipti

HI Karina

Here are some of the effective remedies,you can try

A face mask made with mashed cucumber and rose water is known to be highly beneficial for treating black spots and also improving complexion.

A popular natural treatment for black spot is turmeric. Add some turmeric powder to milk and apply to the spots.

Application of vitamin E oil is also known to help in removing black spots.

Oatmeal, honey, and egg mix together beautifully to make a natural face mask that works for dark spots on face. Mix together and apply it to your skin.

To treat dark spots on face a home remedy that can be extremely effective is aloe vera gel. You could apply fresh aloe vera gel.

Also, when you have the dark spots on your skin, you should always use sunscreen before you step out in the sun. Ideally, you should apply the sunscreen as soon as you step out the bath.