Hi dulcimer dude,
Welcome to Apple Support Communities and congratulations on your new iPhone SE! I understand that when you used the camera with Facebook the screen went green. I can see why you'd reach out about this; I'm happy to help. First, I'd recommend testing to see if the issue occurs in the Camera app on your iPhone, if so you'll want to use this resource: If the camera or flash on your iPhone, iPad, or iPod touch isn't working
If the issue occurs only with Facebook, I'd suggest working through all of the steps below, including contacting Facebook if necessary:
Restart your iPhone, iPad, iPod touch, Apple Watch, or Apple TV. Then open the app to see if it works as expected.
Make sure that your device has the latest version of iOS or iPadOS, watchOS, or tvOS. Then check for app updates.
- iPhone, iPad, iPod touch: Open the Settings app. Tap General, then tap iPhone Storage (or iPad Storage). Tap the affected app, then tap Offload app. Tap Offload app again. Wait a moment for the app to offload, then tap Reinstall App.
If you're having an issue with an Apple app, contact Apple Support. If it's a third-party app, contact the app developer."
If an app unexpectedly quits, stops responding, or won’t open
Best Regards.