It looks like there was no balm used causing the the blade to drag and leave little marks like cuts. Yes you can peel after dermaplane, without knowing what peel has been used it hard to comment, the skin usually does darken after some peels it then peels away after a few days, it's obviously caught where the blade has nicked the skin. It does look like it's been left on too long and has caused frosting on chin. She should definitely go back but she would have signed paperwork to say there are risks during a peel. If that was my client I would like to know what I have done and offer some kind of compensation. It will heal, it looks awful, but you do go through an awful looking stage after a peel, it may just take more time.