Mysql 1 way replication master lost data replication still has
There is no mechanism in MySQL for a master to recapture "lost" (missing, corrupt) data from a slave.  Unless replication is circular (or master/master, where each machine is both master of, and slave to, the other... don't try this at home) then the interaction between master and slave is strictly one-way.  Even in a circular configuration, there's no "recovery" or resynchronization mechanism.

There is also no mechanism for data to be hidden away and reappear.  The comment referencing InnoDB recovering data from log files seems to overlook the fact that this sort of recovery occurs at start-up, and until it is complete, the server doesn't start accepting connections.

The answer should be discoverable in the master's binary logs (you archive those, right?) and the daily backups from master and slave (you archive those, too, right?).  

Absent frequent periodic backups and historical binlogs, it seems difficult to speculate further.