Real Dictionary

dredge up
phrasal verb: If someone dredges up a damaging or upsetting fact about your past, they remind you of it or tell other people about it.
phrasal verb: If someone dredges up a piece of information they learned a long time ago, or if they dredge up a distant memory, they manage to remember it.

dredge up in American English
to unearth or bring to notice

dredge up in British English
to bring to notice, esp with considerable effort and from an obscure, remote, or unlikely source