Eggbound Hognose, help!

My females first time breeding has resulted in 4 healthy eggs, 1 slug, and 1 eggbound egg. We have tried leaving her alone for a few days in her nesting box, we have aspirated the egg (it was HUGE), we've given her a small meal, and taken her to the vet who gave her calcium and oxytocin injections. None of which have worked. She is still active and alert, she passed her meal no problem, if anything it's almost as if she's forgotten it's there! Does anyone know of anything else we can try? Surgery is an obvious last resort.