No. A palimpsest is a physical medium (such as slate or some types of parchment, canvas or clay) that has been erased and used again. This was being written on using a medium (paper) that had not been first erased. The slight difference being that in this case the writing instrument only left an impression and didn’t deliver any ink to the paper.
Don’t get me wrong - it was absolutely lovely of them to do it, it just feels like it was a waste of their time, given that she could have rewritten the lost passage multiple times over. Plus, it sucks to lose a week’s worth of work, but when the solution is five months of someone else’s labor (which, granted, wasn’t actually five months, but still obviously a lot of hours), it’s not a reasonable trade-off, especially since re-writing usually only helps a work.