Zeezrom begins the process of repentance. Note the stages given for his process of repentance:
[was astonished at the words which had been spoken] The first step in his repentance was to hear the message. We need not doubt that had he not heard Alma and Amulek, Zeezrom would have continued in his previous ways.
[and he also knew concerning the blindness of the minds, which he had caused among the people by his lying words] Zeezrom acknowledges his role in the current unbelief. He has personal culpability for his own beliefs, but also a larger culpability for the communal blindness to the Spirit which he had espoused. The recognition of one's own sins is an essential step in repentance. We cannot repent unless we see clearly those parts of our actions, thoughts, or heart that are contrary to the will of God.
[and his soul began to be harrowed up under a consciousness of his own guilt] After recognizing his sins, Zeezrom feels the pains of sin. In this case is soul is "harrowed up." The imagery of a harrow is unique to the Book of Mormon, and comes from Joseph's farming background. A harrow is an instrument for tilling the soil, and as such is much later than the Book of Mormon and Biblical time periods. When a harrow breaks up the soil it digs in and turns in over. Thus when the soul is "harrowed up" it is dug into deeply by the spirit and overturned. Presumably the "underneath" is exposed in both the soil and the soul.
[yea, he began to be encircled about by the pains of hell.] Zeezrom recognizes the consequences of his actions. Not only is there soulful pain attached to the cognizance of his sin, there is an understanding of the direction those actions are taking his soul. He clearly sees that these actions are leading him away from God.
Literary: The location of the story of Zeezrom does not create a formal chiasm, but does follow a structural reversal that is at the heart of the more formal chiastic structures. In the introduction to this sequence Alma provides a small number of people who believe contrasted with the larger number who did not. In this section, we have the large number who accuse Alma and Amulek, and a small number (one man, Zeezrom) who defends Alma and Amulek. That this one man is the defense is a dramatic focus on the turnaround Zeezrom has made. Alma and Amulek were so effective that an accuser became a defender. Yet still they were unable to touch the large numbers who had hardened their hearts.