Awwwww MAAANNN! That looks ugly! It can be fixed, but it won't look nice...
If the scratches are not so deep, you could get away with gluing a piece of stiffer paper over the edges of the scratched area and covering it with tape. It will fly like this, as long as the wing retains it's profile. But if the scratches go too deep, you might have to use some foam filler or something to replace the missing foam.
Remember to balance your plane along the roll axis after you fix it, so that both wings weigh alike.