I need help saving my changes back my google drive

Hello,

I assume you used the "Open…" command in Textastic to open a file from Google Drive.

I just tested it on my device and it worked, but I noticed that I needed to pull down the file list in the Google Drive app to get an up-to-date view of the file changes done in Textastic.

If that doesn't help, you might want to try Textastic's built-in Google Drive client and manually downloading and uploading files. 

Have a look at the following topics in the manual for details:

https://www.textasticapp.com/v7/manual/remote_servers/remote_file_transfer_screen.html
https://www.textasticapp.com/v7/manual/remote_servers/google_drive.html
https://www.textasticapp.com/v7/manual/remote_servers/uploading_downloading.html
https://www.textasticapp.com/v7/manual/remote_servers/quick_upload_download.html