Which is the fastest way of clearing acne?

Internally or externally? Last year, I've been drinking a lot of water everyday for months and I've noticed the pimples on my cheeks have cleared up. This year, I've been drinking one cup of carrot juice every morning and I've noticed a significant amount of the pimples on my forehead have disappeared. However, I have oily skin so I have to wash my face twice a day. It's also occurred to me that whenever I washed my hair, the pimples on my forehead disappear. To me, the topical medication the dermatologist prescribed to me has either never worked or took too long for me to even notice. I really would like to know which method of clearing acne is fastest: eating healthier (internally) or acne cream and oil-free facial washes (externally).