Laura Wearing The Owl Cave Ring

We Laura Palmer's face when it is implied that she tries on the Owl Cave ring, though her hand is cropped from view. We also see a hand placing the ring on its finger and a disembodied hand displaying the Owl Cave ring.

Pausing the film and studying the scene, the length of the nails on the raised hand seem to match the length of Ms. Lee's nails at other moments in the movie. When we see the hands trying on the ring, a small birthmark or mole is visible near the woman's neck. Sheryl Lee has a similar mark near the hollow of her neck.

Noticing the mark, I combined the images of her hand and her reaction. They match after making adjustments to the aspect ratio of the lower image and cropping it. The image of her hands is slightly darker than that of her face. My edit is far from perfect, but it seems to prove Sheryl Lee was filmed trying on the ring. 

The separate images.

Additional photo edits. Those with black framing were made by my sister.