Palimpsest (it’s not a pimple)
From the all-powerful Wikipedia: a manuscript page from a scroll or book from which the text has been scraped or washed off and which can be used again.
You can even make an adjective out of it (although you would think that something is either a pamlimpsest or not):
Etymology (from etymonline): 1660s, from Latin palimpsestus, from Greek palimpsestos “scraped again,” from palin “again” + verbal adjective of psen “to rub smooth”.
And now we shall all remember what palimpsest means.