@Bertie68 - As far as I know the epineurium can't be regenerated, but may be repaired by surgery. Like the article said, there are the three kinds of nerves.
So for the nerves that regulate functions like heart, blood pressure and digestion, not much can be done. Your heart system is at least somewhat affected.
If you have motor nerve epineurium damage, physical therapy can help muscle strength and movement.
Sometimes the nerve coverings of the sense nerves can cause pain. Medication is often used for this.