If you are asking about an "Out of Bounds Effect" Adding an Out of Bounds effect | Learn Photoshop Elements 11 | Adobe TV
then you are using Photoshop Elements and consequently are in the wrong forum. Somehow your thread got posted in the Adobe Premiere Elements Forum (video editing)
Please re-post your thread in the Adobe Photoshop Elements Forum to take advantage of the specialized expertise there.
Please give full details there.
Just some thoughts as you head over to the Photoshop Elements Forum.
What do you want to reverse -
a. After you have hit Out of Bounds before you click Done?
b. Some place between applying a frame and doing selection and background and drop shadow?
Depending on your answer....
The easy part to get back to your original photo would seem to be.....go back to the Expert workspace and delete all the layers in the Layers Palatte above the Background Layer.
But, have you seen the Reset icon at the top right of the Out of Bounds workspace and what it can and cannot do for you with regard to Reverse?