A flexible display panel and a flexible display device are described. The flexible display panel includes a bending region, a non-bending region. A number of deformation detection units are disposed in the bending region. The deformation detection units each includes a first electrode, a piezoelectric (PZT) material function layer and a second electrode which are sequentially stacked in a direction perpendicular to a light-emitting surface of the flexible display panel. The density of the PZT units and PZT function layer thickness may vary depending on their distance from the bending axis.