This past weekend, I was invited by SPANX to head to my local Nordstrom to put to the test the newly launched Power Series (the reformulation of the celebrity favorite Power Panty that put SPANX on the map). To celebrate the launch, SPANX and Clinique have teamed up as Beauty Besties, a pairing of everyday essentials for girls on the go available exclusively at Nordstrom through May. I tried both the Power Shorty and the Higher Power…