Source : Webster's Revised Unabridged Dictionary (1913)

Self-abasement \Self`-a*base"ment\, n.
   1. Degradation of one's self by one's own act.

   2. Humiliation or abasement proceeding from consciousness of
      inferiority, guilt, or shame.

Source : WordNet®

self-abasement
     n : voluntary self-punishment in order to atone for some
         wrongdoing [syn: {penance}, {self-mortification}]