I hope some medically knowledgable person will help me out.
Short version of the question: I need a guy to be stuck in a hospital recuperating for a month after a bad beating. No weapons can be involved, just his attacker’s hands and feet. So what injuries – nonpermanent, non-disfiguring (at least not permanently so), and ideally non-life-threatening – can I give him?
Hm, I guess I should explain. Don’t worry, I’m not some violent wacko. Well, not in real life, anyway. I’m rewriting an old serialized story as a sort of retcon, and I need to fix a plot hole that occured as a result of bad planning.
Slightly longer version: This man (he’s about forty, if his age helps) has been badly beaten by a goon to whom he owes money. One thug is holding his arms back, the other is punching him. Originally, I gave our hapless victim fractured ribs, a broken nose, an unspecified wrist injury and a broken leg. The guy was supposed to be hospitalized for less than a week. But he wasn’t released until a month later of story-time. Now I’m rewriting this to fix the timeline and make it marginally more credible, so the injuries need to be more severe to justify the month-long hospitalization. What can we give him?
Long and boring explanation interesting probably to no one but writers, and possibly not even then: What happened was, due to various plot/pacing problems that developed when I stupidly wrote off-the-cuff rather than planning things out properly, the length of time the character spent in the hospital was extended from a few days to a month. Which these days is pretty rare, I’d imagine, and certainly for such relatively minor injuries.
Originally, these discrepencies weren’t so glaring, because the serial’s installments were published at a very slow pace, and I was able to sorta cheat/blur over the chronology of the storyline. The readers probably forgot the original injuries by the time the character finally left the hospital. But now that I’m re-reading the serial archives one after another – which is how new readers will be seeing the story – the timing is glaringly off and it’s bugging the hell out of me. So I want to fix it. It won’t affect the ongoing story arc in future – that’s why I don’t want the injuries permanent – just anyone reading the serial for the first time.
I know I deserve mocking for being so sloppy in the first place! But be gentle, please. 
Mods: I think this is a GQ – the basic question is medical in nature. If, because it’s a fiction thing, this needs to be moved to CS, please go right ahead! And sorry for misjudging.
As much as I’m trying to fix my story so it makes more sense in retrospect, I gotta accept that this month-long hospital stay is never gonna be especially realistic no matter how I tweak the original setup. My goal is to make it slightly less ridiculous by giving my character injuries that are more severe than those he originally had.