Lyric discussion by Caecus 

Cover art for Iodine lyrics by Leonard Cohen

In keeping with the theme of the record (the "death of the ladies man"), it's a song about impotence. Much of the first side of the record is about emasculation (impotence, cuckoldry, voyeurism, rejection) building to a depressed and demented male libido and ego on the B-Side. The metaphor here is that iodine is used to treat wounds, and the woman's (a sex worker?) compassion to him in his moment of humiliation feels like a wound being treated.

"I needed you when I knew I was in danger/ Of losing what I used to think was mine" is perhaps an indication that the woman's role is a service role, ie sex work, and what he is worried about losing is his masculinity. "You covered up the place I could not master/ It wasn't dark enough to shut my eyes" the place being his penis, which remains embarrassingly flaccid and out of his control, and the lights being on indicating that this is likely a casual or procured sexual encounter.

Like the next song, "Paper Thin Hotel," the narrator learns that what he had feared, losing his perceived manhood, is possibly a blessing. "And all my wanton lust was iodine/ My masquerade of trust was iodine," indicates that he was using his masculine posturing and sexuality to cover up deeper wounds in his character. He's learned something about being a better person, and a better man, we may guess).