Los Angeles:Actress Keira Knightley says she never did anything to her skin until she got acne. The 31-year-old, who has been the face of the luxury designer brand Chanel's beauty campaigns, says she only wore smudgy eyeliner when she was a teenager, reports femalefirst.co.uk. "I didn't do anything with my skin until I started getting acne, at which point I did everything possible to get rid of it. I tried a million products, but none of them worked,” InStyle magazine quoted Knightley as saying. "I had bad skin until I was 25. I later learned that it was more about diet and hormonal changes,” she added.