The way I would do it would be to select those portions of the image that you want to be white. Since they are now purple, you might use the "Magic Wand" since it selects on color. Remember that you can change the Tolerance to help select what you want and can use the "Add to existing selection" box. Also checking or unchecking the "contiguous" box can often help. The selection brush can also help if your version of
PSE has it.
In any event, select the portions of the image that you want to be another color. Do a "control J" which will put the selected area on its own layer with the rest of the image transparent. This is not immediately obvious because the image of the original layer shows through. Click the eye to hide that layer and you will see your selection alone on its layer. Select the transparent area with the magic wand and then "Select Inverse" from the Select drop down menu. You may want to put a "feather" on this selection. Make your Foreground white and use the Paint Bucket tool to fill the selected area with white. Make the lower layer visible again. You may wish to play around with the Opacity of the layer so the white isn't so overwhelming. Also try the blending modes on this layer.
Be sure and make a duplicate of your original image and work on the duplicate. This allows you to discard your work at any time and start again, on a new duplicate. I also usually made a duplicate layer of the background layer when I work. Many things can not be done to a background layer.
Hope this helps.
Cobalt