Maybe it would be possible to use a sock. You could probably use a white sock and draw a line around the bottom of it while it is on your foot. Then draw a line straight up the back and another line straight down the front of the sock. Take the sock off and cut along the the lines. You should have three peices. Trace these peices onto the neoprene, cut and glue. I would guess that it might take a few tries to get the right fit. good luck.