Ah, August. Back to work. Back to school. And looking back in the mirror is the evidence of how much fun I had in the sun this summer: Freckles, wrinkles and dark spots, especially on the sides of my face where my hat didn’t cover. Once upon a time, I might have reached for a prescription or over-the-counter skin lightening cream to combat this kind of sun damage. But I know now that hydroquinone, their most common ingredient, has been linked to cancer and, ironically, ochronosis, also known as skin darkening. Yikes! That’s why this DIY is such a relief: With two kitchen cabinet ingredients and five minutes, you can…