The British actor Jamie Bell has soft eyes and a bashful demeanor, both of which served him well as Bernie Taupin in the recent Elton John biopic, “Rocketman.” These traits must be virtually erased, however, to play the real-life former white supremacist Bryon Widner in “Skin,” a blistering story of rage and redemption that never fully illuminates the journey from one to the other.

That’s not because Bell’s performance is wanting — far from it. Like Edward Norton in Tony Kaye’s incendiary 1998 drama, “American History X,” Bell transforms convincingly from slogan-spewing skinhead to decent human being. Unfolding in flashback as Widner undergoes multiple agonizing treatments to erase the vile tattoos that blanket his face and body — a literal and metaphorical personality peel — the movie immerses us in the dark heart of white power.

What it doesn’t do is expose the psychological soft spots and belief systems that allow extremism to grow: Widner’s neo-Nazi views appear more the result of habit than philosophy, absorbed incrementally from the heartland hate group that virtually raised him. Consequently the story, pumped up with the now-familiar “Blood and Soil”-yelling meatheads, centers mainly on the physical perils of his decision to leave; his ideological conversion, if it exists, remains stubbornly veiled.