This is what waec says about remarking of exams.
Review of Scripts
Schools and individual candidates may request review of their scripts after the release of results.
The request for review arises from dissatisfaction with a candidate’s results and the desire to know what might have accounted for such a performance;
The review of scripts is done with a view to identifying the weaknesses of the candidates and correcting any defects in teaching and the way candidates tackle questions; for school-based examinations, requests for review of their scripts are entertained from heads of schools; Private candidates also may request for review of their own scripts. It must be noted that worked scripts are kept for only three months after the release of results. In view of this, all requests for review should be done within the stipulated period.
The review of scripts attracts a fee that is reviewed periodically.
Request for the review must be made formally to the Senior Deputy Registrar/Head of Test Administration Division.
You can call waec head office 0302-685901- 4 for further clarification
Also you can do remarking through your school by letting your school apply in your name.