Can anything be "forgotten" once it's been determined? For example--can two entangled particles be created, then forced to interact in a way that collapses the

Can anything be "forgotten" once it's been determined? For example--can two entangled particles be created, then forced to interact in a way that collapses their wave functions, then sucked into a black hole, without having been observed by anything that isn't sucked into that black hole--does their collapse matter? Does the universe forget it? If so, then could the whole universe be a reversible computation, once it's summed up from big bang to big ... whatever happens at the end?