Why exactly is Pryor rebounding? I haven't seen anything come out of Arkansas that suggests that the climate shifted.
Assuming that Nate Silver is correct about internal polls giving a 6 point bias to the party of interest, then Cotton should be up about 3 points, which when averaged with the Talk Business Poll gives a tie.
Looking at the polls that have shown Cotton ahead, all of them have been either Republican firms or Rasmussen (or do I repeat myself), so I would question whether Pryor has actually rebounded or if Republican-slanted polls were accepted prima facie due to confirmation bias of preexisting notions of Cotton's inevitability.
