I bet it means that any damage they took while DR’d gets reversed but they don’t fully heal
So Xebec’s injuries that he took from Imu/the Davy Clan prior to getting DR’ed did not heal, but the damage Roger and Garp did to his DR form did heal. This is why Xebec is still damaged after coming out of DR.
I doubt Oda intends to have Imu healing his enemies lmfao.