Also, didn't check the image before posting. That does look like possibly some dry skin from a previous shed. The edges look too noticeable for it to be from skin that's about to shed for me... But maybe someone else can chime in on that.
My concern is if there's tape on that box I would take that out asap. Tape and snakes is a very, very bad combo. If the snake is shedding and starts to rub and pulls up a bit of tape, the adhesive can seriously injure them.