Even after leaving the third area, Elaina is still not devoid of the worries but who wouldn't after witnessing the Snow Men themselves? And with those igloos bringing the danger further, more Snow Men are spawned. Leaving them alone will spell trouble and Elaina doesn't want that to happen.
However, dealing with all of them and finding them is another big job altogether and Elaina is not going to do it. After all, she is just a regular farmer with an occasional usage of sword as a weapon but other than that, she isn't that much compared to real adventurers who make a living risking their lives to deal with monsters.
Right now, that is Elaina's least of concerns.