I believe the marring was primarily wounds, blood and gore causing the disfigurement, as Isaiah also says not a bone will be broken, etc.

As bad as this was, it seems quite likely that Joseph of Arimathea and Nicodemus, in preparing His body for burial, would have done what they could, in terms of ‘tidying up’ - minimally I would imagine wiping his face and whatever blood they could, on the rest of him, before wrapping him in a clean linen, as mentioned in the gospel accounts.

The shroud research just keeps turning up new discoveries. One of the more recent things is the recording of motion, as if the body were preparing to arise.