Why isn't Metta melting my harsh inner critic fueling depression?

It is an incredibly harsh inner critic that drives my depression. I require a meditation that has a particular focus on melting this critic and restoring my self-worth. Can the most direct and powerful guided practice be a Metta meditation to actively heal the negative self-talk of depression? My name is Akash, from Delhi. DOB: 17th September 1991. Time: 5:45 PM.