The reason you probably have a headache is because the anesthesiologist punctured your dural sack while inserting the epidural. Now CSF fluid is leaking and throwing the pressure off in your head. So they sterilely draw your blood, insert another epidural and push the blood through. It finds the hole and plugs it. Hole is sealed, pressure stabilizes and headache goes away.
Yep. 48 hours later. No one believed me for 2 more days. Told me i must have a cold. I was in agony. They did a blood patch and I was better an hour later