Spring is here and with it bare legs and arms. And although we all know we should just accept the skin we’re in and eschew that sun-kissed look, there’s something about pale and pasty that’s just downright bad for the old self-esteem. Now, that doesn’t mean head up onto the roof with a bottle of baby oil and a roll of aluminum foil—that’s so junior year 1998. Nor does it mean slathering on some potentially carcinogenic self tanning chemicals that turn you orange. Actually, the active ingredient in most self tanning creams isn’t so bad. Known as DHA, dihydroxyacetone is a sugar that can be derived naturally from beets; it…