My tray this week has a black mark in the top tray. It's very unsightly. What should I do?

The trays have identification marks on the occlusal surface and time/wear indicators on the very back of the aligners next to the cheek.  These are normal and no one will see them. If it is something else or somewhere else on your aligner, then call your dentist to have them figure this out.

Invisalign Teen has two dark marks in the top back.  They will change color per your wear time.  If you are seeing something else, you need to inform your dentist and maybe they can polish it out.