Help! Mischa Barton needs some mascara, some Swiffer pads and a bag of Doritos, STAT!  We spotted the former O.C. star at a Rite Aid pharmacy in Beverly Hills yesterday.  Mischa, who hasn't done much acting these days, has recently launched a line of headbands (yes, you read that right).  Her exclusive headwear will be sold at boutiques Rouge, H. Lorenzo and Jennifer Kaufman.