Rob Lowe, who was mercilessly mocked on a Comedy Central roast last week, is in our midst. The former Brat Pack actor best known for his role on “The West Wing’’ (and in that infamous sextape with an underage girl way back in 1989), has a part in “Super Troopers 2,’’ which is filming now in Boston. Lowe plays a former hockey player who’s the mayor of a small Canadian border town. The cast also includes “Wonder Woman’’ Lynda Carter and “Bourne Identity’’ bad guy Brian Cox.