I am 23 and I have pimples and holes on my face. And slowly becomeing dark. And also I have un wanted hair on my chin how to cure suggest me?

Seek treatment. Pimples cause inflammation in the skin. When the inflammation subsides it often leaves discoloration. The way to prevent this is to seek treatment for your acne from a good dermatologist. He or she will also have treatment options for your unwanted facial hair.