3 And also Zeezrom lay sick at Sidom, with a burning fever, which was caused by the great tribulations of his mind on account of his wickedness, for he supposed that Alma and Amulek were no more; and he supposed that they had been slain because of his iniquity. And this great sin, and his many other sins, did harrow up his mind until it did become exceedingly sore, having no deliverance; therefore he began to be scorched with a burning heat.
Zeezrom is one of the Book of Mormon’s best examples of the principle that no matter what we have done wrong, God can deliver us. Just like Saul of Tarsus, his actions had led to the death of many faithful believers. Yet, he was struck by the teaching of Alma and Amulek and came to repent.
I also suspect that Alma must have taken somewhat of an affinity to Zeezrom in light of the parallels to his own father’s conversion.
Zeezrom feels the full weight of what he has done, but does not fully yet understand how to repent and call on Christ. So he suffers in great agony until he can be taught be Alma again. And then, he learns to call upon Christ and to experience the healing light of his forgiveness.
This is why missionary work is so essential. The light of Christ brings feelings of guilt when we have done wrong, but without being taught of Christ we do not know how to overcome that guilt and shame.