If the opinion of the marji' that you follow is the obligation to cover the face, then it is not permissible to refer to another marji'. If his opinion is a compulsory precaution, then you can refer to the opinion of another marji' provided that he is the most knowledgeable than the rest of the other maraji'. If the opinion of that marji' is permissibility, then you can uncover your face based on the second marji's edict. In any case, it is not obligatory to cover the face according to his eminence, Sayyid al-Hakeem, may Allah prolong his life.