That sounds so sad after you sewed the top and probably quilted it yourself. I, too, would de-lint it and put a note in the present telling the girl about it linting so much. Or, as someone else said, put a different back over it and tack it on. That sounds like it wouldn't look as nice, but I sure wouldn't want to have to un-quilt it. But if you have the time and energy, redo it. Good luck! And you are so nice to go to all the trouble to make a baby quilt for someone. It's a lot of time and work and money.