Sad, but not I think unrepairable or unrecoverable or irretrievable.
Prepare to get lots of packing paper. Hun is ideal. A few days worth. Loosen off any residual tension.
Soak the lot in warm water for about 24 hrs. Dry it out while stuffing the shape back into it using the aforesaid newspaper. Monitor the drying, the shape and keep renewing the stuffing with dry paper. When it is dry, remove the paper. It should now have the correct shape. If it doesn't, repeat the exercise and get it right. It may take anything from three days to a week to dry out. Now give the underside a bath in Olive oil. I do not know if there is an advantage in using extra virgin but I suspect not. Let the oil soak in . Remove the surplus and then, carefully re-tension. The holes, if they exist, in the saddle are a nuisance for this operation, so you will need to block them. Plasticene, Blue tack, paper and sellotape can all be used to block the holes.
All care and no responsibility.
Jur on these forums has previously done lots of work with leather saddles and could possibly help.
Stay fixed. Keeping a cool head.