Is it beneficial to do Masters in mass communication after BJMC?

Yes, it is. Any post graduation leads to a strong knowledge and skill enhancement. In the case of B.J. M. C. to M.J. M. C. it actually gives you many reasons to do this degree. M.J. M. C. makes you eligible to Appear of UGC NET. It is the minimum Requirement to be a PRO - (Public Relations officer).