Ashlee Simpson insists her smooth skin is down to a tweezer "whizz" not Botox.The 23-year-old singer - whose father Joe recently confirmed she had rhinoplasty to reshape her nose and help her breathing in April 2006 - insists her smooth skin is down to the work of her great make-up artist. Her spokesperson said: "Ashlee has never had Botox in her life. She credits her eyebrows to her make-up artist who is a whiz with the tweezer."Last week, it was reported Ashlee visits plastic surgeon Dr. Raj Kanodia every month to have collagen filler injected into her face. A source close to the singer said: "She is determined to stay looking as young as possible for as long as possible. The fillers get rid of any wrinkles, and keep her face looking young, taut and smooth."Last month, Ashlee's dad ignored his daughter's wishes by speaking publicly about her nose job.Joe - who also manages Ashlee - said: "Girls have their own ideas. Anyway, there was a real problem with her breathing and that was cured."