The shrinkage process that results from the reversible deformation of high-density polyethylene (HDPE) via the crazing mechanism has been investigated by atomic force microscopy (AFM) and X-ray scattering. It has been shown that the fibrillar-porous structure resulting from HDPE crazing in a physically active liquid medium (ethanol) undergoes substantial changes during the shrinkage: in the AFM images, separate lamellae and fibrils are replaced by new structural formations, which seem to consist of lamellae and fibrils. A procedure has been developed that implies creating a lithographic label on the surface of a deformed polymer to navigate over the sample surface with a high accuracy (down to a few nanometers and individual lamellae) and in situ observe the structural transformations accompanying the shrinkage of HDPE. The study has shown that the transformation of the structure upon the shrinkage is associated with different factors, including the "attraction" of fibril material to lamellae after load elimination similarly to that taking place in an elastic band. X-ray scattering data have shown that deformation along the extrusion direction leads to molecular orientation of HDPE by orienting lamellae and fibrils in the stretching direction, with this orientation remaining partly preserved after HDPE shrinkage. The SAXS data have confirmed the conclusions inferred from the AFM studies that fibrils are formed in the HDPE structure upon crazing and disappear upon shrinkage.