This is easy to fix and only takes a few minutes to do. Take a new single edge razor blade and cut the tissue along the rib, on the same side as the wrinkle.

The tissue will now be able to hang freely.

Flip the wing over, and using a pin, push the tissue back over the top of the rib.

When you are done, the tissue will overlap a little bit on top of the rib.

On a piece of cardboard or paper, mix a drop of white glue and a drop of water.

Use a small paint brush, and brush the glue solution over the tissue paper seam.

Do this to both wing tips, and let it dry for about an hour.