Gospels Mark and John are silent about Judas after his betrayal. Luke continues (in Acts) with different details than Mathew's here, "..And he cast down the pieces of silver in the temple and departed and went and hanged himself. And the chief priests took the silver pieces and said "it is not lawful to put them into the treasury because it is the price of blood". The illustration is Judas seeking pity from those he marketed his betrayal to.