Antiseptic or antibacterial property of haldi or turmeric makes it a good herb against acne/pimples. Because of these ayurvedic properties of haldi or turmeric, it is used to treat many skin conditions including acne/pimples.
You can make a paste using haldi or turmeric to apply over the face. This haldi paste should include bit of water and aloe vera as well. You can apply the paste over your face twice a day. Avoid around the eyes. There are reports of consumption of 1 teaspoon in 1/4 of warm water 3x a day reduce the occurrence of acne and acne inversa as well.
Most of the modern facial washes and sunscreen contain haldi or turmeric as a component. Antioxidant property of haldi or turmeric is used in sunscreen and facial washes.
Haldi or turmeric (Curcuma longa) is an herb which belongs to ginger family. It grows in tropical areas of south asian region.