I hope this gets remedied to your satisfaction! But I personally think the best way to learn to deal with things that bother you are to first address it with the person in question. From your post, it sounds like it’s possible/likely you haven’t discussed the smoking/smoke smell with your roommate ever. I see that you requested a non-smoking room, so it’s irritating that you have to deal with this at all. But to me, it’s crazy to elevate something like this without at least having a conversation with your roommate first.
For all we know, this kid didn’t lie on his housing form, and may have freely said he smokes. They may have just assigned the two of you together either as a mistake or lack of appropriate accommodations. Or maybe the school wasn’t clear, and asked if the student was happy to live in a no-smoking room, despite being a smoker. It sounds like up until being alone over the long Thanksgiving break, the student has respected the rule about not smoking in the dorm. It was wrong for the roommate to smoke in the room over break, but I’m sure many college kids have done things in their rooms that they shouldn’t. I am sympathetic to the awful smell of smoke and being upset your clothes smell (both my parents smoked when I was growing up and I HATED it). But to me going over his head (ie. tattling) without initially addressing it with him is terrible. I have no problem with you going over his head if he responds poorly to your request that he cease smoking in the room, although I’d be clear with him that that’s your plan. But he deserves to know that it is bothering you before you elevate it. He may have no idea that you gag a little in your mouth every time he walks in the door with his stench. He may be happy to bend over backwards to prevent that in the future—it is appropriate to give him a chance. I don’t understand how you can live with someone and never talk, or raise any concerns. This is one of the great lessons of freshman year—learning to live with people who may be different from you, and how to negotiate, accommodate, work together towards solutions.
Now assuming that the roommate will not ever again smoke in the room, but you still don’t want to live with him anymore because you don’t like the smell of the roommate, it is an interesting question about who needs to move out. I would assume that you would be the one requesting to move, or at least be willing to. I wouldn’t go into this assuming that you can get the roommate kicked out of the dorm because you don’t like the way he smells. If he violates rules (smoking in the room), I would assume there would be more of a case that he have to move, but probably not with just one violation, assuming he wants to stay. So if he’s never going to smoke in the room again but you want to split up, you may need to be willing to relocate.
Good luck, this stinks (literally).