The way I imagine it, rather than getting beaten up, the guy is simply held down and cut once with a razor. The other inmates take turns spitting into his wound and saying, "I wish I could afford the medications that keep my HIV under control. And now you do, too."
But I just imagine that. It's not like I would ever attempt to actually set up such a thing.
Or I imagine that he goes in, and most everyone is kept segregated under extremely high security, with leg shackles and spit masks. He is put into a cell, and his cell mate has a horribly scarred face, but a bright, friendly grin, insomuch as the scars allow it. That night, he wakes up, unable to move, as the razor blade digs into his face. "I used to have that pretty face. Why should you get to keep it?" The next morning, his cell mate is taken away to solitary. A few weeks later, after his wounds heal, he gets a new cell mate. Lo, it's Martin Shkreli! So he flashes a bright, friendly grin as he thinks about his hidden razor blade. Rod Serling narrates us out, talking about the prison where all the other prisoners are copies of you.
We need to imagine prison as a terrible place, where bad people get punished as they rightly deserve, because we need to believe that putting people inside actually somehow serves justice in a useful way.
He won't get beat up in jail because he deserves it, but because he will find no one inside willing to watch his back, and the other inmates will attempt to extort some of that pharma-CEO cash out of him while he is within their reach.