The Paralympic Runner claimed his wounds were sustained after falling from his bed in Pretoria’s Kgosi Mampuru prison.
He was immediately rushed to the South African capital’s Kalafong Hospital.
Two wardens later revealed the convicted killer was found to have blades stashed in his cell.
Another inmate said the wounds had been inflicted by Pistorius himself around midday yesterday.
He has returned to jail after receiving treatment in hospital – where he was surrounded by an armed guard.