By the end of Othello Act II.iii, Cassio is very worried about his reputation, which, like a "soul," he calls the "immortal part" of himself:
Cassio has lost standing as Othello's lieutenant and fallen so low that he must ask Desdemona, a woman, to put in the good word for him with her husband. So, Cassio has gone from "the chosen one" to "outcast," from the rank of "right-hand man" to below the rank of women. He is alone, on an island, away from home, struggling with a disease (alcoholism), during war, and his only advisor (Iago) is pure evil--a horrible turn of events for the once "golden boy."
Cassio is very angry at himself for having gotten drunk. He calls his condition the "devil drunkenness." Like Othello with jealousy, Cassio becomes a monster after drinking. He has no defense against his condition, and he knows that Othello will never trust him again for fear of being drunk on duty--a cardinal sin for a soldier during wartime.
Cassio is confused about who to trust: Iago or Desdemona. Iago urges him to not be so hard on himself and seek Desdemona's help. Cassio agrees, playing into Iago's plan of revenge. Later, Iago will use Cassio's secret pleadings with Desdemona as evidence of an affair. So, Cassio is torn between all options: he cannot go to Othello directly (he is too angry), so he must go through Iago (male villain) and Desdemona (source of jealousy) to retain his repuation. All options lead to death.
Ironically, Cassio is not exactly worried about who he was fighting: was it Montano or another mystery man, Roderigo? Since it was night and he was drunk, Cassio internalizes the problem, blaming himself and selfishly seeking to restore his reputation. In other words, he is not at all worried about the men he might have injured.