I woke up with a dark strip on the top of my gums.. what is it?

In order to diagnose this, it would need to be looked at by a doctor or dentist. Your dentist may be able to make a diagnosis so if this continues to be present, you can see your dentist. Are you having any symptoms associated with the dark strip? See your dentist for diagnosis and treatment, if needed. Good luck!

"Dark strip" is not a diagnosis. To answer your question you have to be examined,, either in person or on a teledentistry site. This is an educational, not a diagnostic site. And no, we do not have the capability to examine your photos.