I stretched the vinyl too far and it's out of shape.

GunSkins is made from a heat stretch vinyl. When hit with heat, the material becomes loose and malleable, which helps it contour around edges, corners, dips, and protruding pins. However, sometimes stretching the vinyl can cause a lot of tension, especially when working with a large piece or wrapping a rounded edge. This can cause wrinkles and warping of the material, making it uneven even if you peel it back up. Instead of a flat piece you may hold something that is wavy and out of shape.

Don't worry, if you hit the vinyl with an even heat up and down it will help to reset the shape to the way it was. Careful not to use too much heat on a single area. Its best to spread it out instead of focusing on a single area. When cooled, the material will harden again and you can give it another attempt. Be careful when installing, it is possible to heat the vinyl too much and stretch it too far. It's not without its limits. If you get a rip, tear, or hole, it may be possible to cover it by patching a new piece of vinyl right on top.