According to research you must apply fresh aloe vera gel on the dark spots before bedtime. Rinse the face in the morning with warm water. Licorice extract: Glabridin in licorice inhibits the activity of melanocytes, therefore helping in skin lightening. Creams containing licorice are available as over-the-counter (OTC) topical products. Salicylic acid: This active ingredient helps unclog pores and prevent new acne breakouts. Retinol: This can unclog pores and fade dark spots. You'll find benzoyl peroxide, salicylic acid, or retinol in acne products that you can buy without a prescription. Lemon is loaded with Vitamin C, which can help in lightening dark spots on the skin. You can try spot treatment and rub lemon juice on the affected area for a few seconds. Once dry, rinse the area with cool water. Repeat this process every day to fade the spots.
But for me, I use Honey & Cinnamon to give the dark spots away. I do this everyday and it helps me. But yes the lemon does help as well you'll just feel a bit stinging.
Hope this helps /~θvθ~\