i wash mine in a lingerie bag with the rest of my wash and then lay it flat to dry..there's really no way to prevent little strings from popping out but i think this way creates the least amount of damage...if you're really worried about it, i would hand wash it.

i think the only place that the sweater is actually fitted is in the forearms. i have pretty big wrists so i guess my forearms would be a bit larger than normal and i got a large which is my normal size and it fits fine. the sleeves slouch a little but i can't really roll them up. you'd probably be fine with a small or medium.