I'm developing a login page for my Django application and am using Google login for users to gain access. My question is if they sign on successfully, do I need some way to change the state of their sign on for security purposes?
Might be a silly question but I honestly have no idea and want to be sure.
No, not a silly question but a thoughtful one.
Using Google or other OAuth2 providers for your login is Ok, you request a set of scopes and when your user login and accepts to continue, you can make requests within those scopes. The flow is outlined here for Google https://developers.google.com/identity/protocols/OAuth2.
Generally, you won't have far-reaching access to manipulate users' accounts and for some scopes, your app needs to be verified. For web applications, remember your users will see the scopes you are requesting and can always decline. Because of this, it's generally a good pattern to request the scopes when you need them.
If your public application uses scopes that permit access to certain user data, it must complete a verification process. If you see unverified app on the screen when testing your application, you must submit a verification request to remove it. Find out more about unverified apps and get answers to frequently asked questions about app verification in the Help Center. https://developers.google.com/identity/protocols/googlescopes
That's Google trying to keep users safe.
By the way, users can always revoke the access they have given your app at any time and for any reason.