Plants cannot heal damaged / melting leaves so I would remove the melting leaves, manually clean up the algae covered leaves (toothbrush or something should work) and do a 50% water change to dilute the organic matter from the melt. Then leave everything left alone for a couple weeks to see if new shoots come up. Most plants bounce back (I lost some Bucephalandra at start up but everything else that had melt did re grow after a few weeks)