A horrifying dichotomy for Amai-mask to reverse his transformation and remain in his monster form when he's first and foremost, a hero in heart and mind and then be treated as a monster because of his outer shell. Who just mere moments ago, was told by Saitama that regardless of appearances and how he's being seen, he's still human and he got the courage to discard his human transformation despite everyone seeing him, effectively ending his hero career.
His worst nightmare would be to become that virus that ravages the world of OPM as the monster, instead of being the hero immunization system that cures it. It must be terrifying for him to have the sense that his consciousness is fading as he cannot concentrate enough to transform back into human. (Chapter 216: Monster)
All is not lost however, because even as the urge for senseless violence wells up and the drugs to his brain overtake his system like they did with humans like Choze and his subconsciousness is lifted of any restrictions, his morals and sense of justice have carried him this far and the words of Saitama echo in his brain. He's not like Gouketsu or Choze who chose to monsterize to attain power to kill others and he's not without a moral compass unlike people like Choze who revel in their bloodthirstiness, cruelty and callousness. (Chapter 72: Monsterization)
Amai-mask may be vicious to monsters, but it was always aimed at evil-doers so there wasn't anything to amplify when his monster genes try to pit him against humans.
There are characters far, far more revolting than Amai mask in his monster form in this manga, the same Amai-mask that saved the ferris wheel and asked if anybody was hurt, but it is my theory that exactly this is enough to give him hope to reverse monsterization and attain back his human form given time.
The demonsterization segment has been since redrawn but Hamukichi's resolve to turn back into human is important in the separation of monster cells from humans. As confirmed by Blast, psychological state is the key. (Redrawn chapter 196: Threat)
I predict that Amai-mask might be willing to submit himself to testing for demonsterization which would be a breakthrough in terms of turning monsters back to human, if given the chance to do so and tracked down by someone like Saitama or Blast.
And if anyone could do it, it's probably Amai-mask with his resolve to attain back his human form, his sense of justice and morality and not completely succumbing to the violent urges of monsterization like many, many others who monsterize. With enough media scrubbing and good publicity, he could work in public as a hero again too if he succeeded. Both Amai-mask and Hamukichi are polar opposites to someone like Choze who had little morals to begin with.
We've also probably not seen the last of Hellfire and Gale, because they've not been turned in for experiments yet and could offer another breakthrough in the experimenting of reversing monsterization. Last time we saw them is in Chapter 203: Fever, chasing down Flashy flash. Perhaps Flashy flash apprehended them off screen and turned them in like he originally intended before distractions, who knows. (Chapter 199: Close call)
In the meantime, I'm itching to see where Amai-mask's monster form takes us and how he resolves the pickle he's in. Thankfully Saitama is already en route to help him after seeing him transformed on live tv, in a rare case of seriousness and expediteness because he understands completely what must've happened to Amai-mask and what follows up on the monster reveal, having faced the crowd disgusted by him before.
Amai's redemption arc is the reason why Narinki's squad was spared in the redraw, because Amai would regret killing humans controlled by monsters later. And because the very same squad would also speak on his behalf about his good character, despite him being a monster.
"Isn't it more about what you are, rather than how you are seen? We're all human after all..."
