I've had them twice, plus I've stayed in dirtbag hostels/hotels that were infested with them. But thankfully I didn't bring them home with me, somehow. I had my clothes cleaned as soon as I got home.
It was horrible, I don't know what else to say. It's not the end of the world but I still get paranoid that I have them if I see a red bump anywhere. Just thinking about them crawling over me and feasting is fucked. Like you said, it'll be inevitable that they'll come for you. A new bite will be very itchy very quickly, then subside - it's worse than household spider bites or mosquito bites, at least it was for me - felt like small fires had just been ignited on my skin. And they bite more often than spiders in my experience.
Their bite sizes vary but judging by your roommate's situation, the bites will probably be big. They also bite in patterns, triangular or three in a row. People say the bugs prefer hairless areas but I still got rough bites on my legs, which are hairy.
Cleaning can help the situation, but don't try to kill every single bug b/c that's probably impossible since they hide. Really, the only thing that can get rid of them permanently is letting pest control specialists handle it, which is what I did. For me, they had to spray twice - once to kill the adults, then another time to kill the babies. Make sure you do it twice, it's crucial, trust me - the wave will start again if not. And yeah, you'll have to wash all your clothes as well.
I never tried using bean plants, but maybe this could help:
http://www.nytimes.com/2013/04/10/science/earth/how-a-leafy-folk-remedy-stopped-bedbugs-in-their-tracks.html?_r=0Hope this helps!