Sun/liver spot removal?

I am 28 yrs old and have fair skin. I have never been one for tanning in my younger years & have never gotten sunburned. Everyday I use SPF 15, I wear a hat when going out & in general I avoid the sun like the plague.At a very young age I have been anti-age obsessed, unline the other girls my age who would tan. So you can imagine my shock when on my left cheek I developed a SUN SPOT! First, I can't imagine how since as I said I take so many precautions. And 2nd, I want to get rid of it. I went to a dermatologist who confirmed it was a sun spot. She put me on Tretioin 0.25% cream. However, creams like Retin-A, hyrdroquinone tend to scare me.For one, I really don't want chemicals on my face. Hydroquinone has cancer causing properties and is banned for use in Eurpoe. And Retin-A may actually WORSEN hyperpigmentation on spots and can reoccur once you stop using it.
What I am looking for is a NATURAL way that is effective in PERMANENTLY erasing this spot!!!!!!!!!

try applying lemon juice to the spot, avoiding the eye area since that would sting. Esoterica cream, a long-marketed product available I believe at Wal-Mart, is also a possibility.