Saddles wear out, you know...WAY before 13 years. I’d say get another Selle Italia C2, maybe even the gel model with the cutout if you want to get fancy. I also agree with the trainer comments above. I think almost nothing helps on the trainer except trying to force yourself to change position and standing frequently.

https://www.selleitalia.com/en/saddles/c2-gel-flow/

Just don’t wait another 13 years to replace this one, lol