I can't think of anything that won't show a little bit.
I did hand-darn a tear that my cats put in a quilt. It was very very hard to find again - but it was on a printed part of the fabric.
One can put a piece of fusible tape under the tear, very carefully pull the edges of the tear together and fuse it. Then maybe do some hand-darning on that, too.
Is this on a solid color or does it have a design where stitches won't show much?
Does this belong to you or to someone else?