Welcome, @wlgiles. Seeing something out of the ordinary can be quite disconcerting. I'm sure you are concerned. You might be interested in reading this related discussion where @lls8000 @merpreb help explain ground glass:
- What is ground glass on a lung CT scan? https://connect.mayoclinic.org/discussion/what-is-ground-glass-on-a-ct-lung-scan/

It sounds like your team wants to keep an eye on this, hence the next CT scan in a month. Keep in mind that ground glass can indicate a number of things that are not cancer, like an infection. Have you had an infection lately? Did you review the CT scan results with your doctor already?