An Observation: Sub-Orbital dark Shadows

Good day amazing people,

I would like to share an observation. My daughter's classic look of sub-orbital dark shadows has been present since onset of ME. She recently underwent surgery and was put under anesthetics, about two hours. Due to the heavy sedation, she continued to sleep for another 5 hours. The following morning, her dark shadows were gone.

....They ultimately returned as the days went on, but I found it interesting. Are they attributed to the utter lack of deep, restorative sleep? And just a few hours where she was completely knocked out made so much difference?

Take care everyone.