Hi CaitlinHemsley,
Thank you for reaching Microsoft Community. I'm sorry to hear about the issues you have experienced with your Surface Book 3 especially with the camera issue you are having right now.
Kindly follow these steps below to troubleshoot:
1: Make sure Camera is enabled in the UEFI settings
See this page for the steps on How to get to the UEFI settings
On the UEFI screen, go to Devices
Make sure that the IR, Front and Rear Camera options are enabled
If already enabled, disable the options for about 10 seconds then back to enable
Select Exit > Restart now
2: Run Surface Diagnostic Toolkit
See: Fix common Surface problems using the Surface Diagnostic Toolkit (microsoft.com)
3: Check for Windows Update
Go to Windows Settings > Update & Security and select Check for updates
Make sure all updates need are installed including Optional updates
4: Update drivers and firmware
Check what is the current OS Build of your Windows version by going to Settings > System > About.
Go to Download driver and firmware for Surface, choose Surface Book
Then click the link next to Surface Book 3 then click Download on the next page.
Choose the .msi file that matches your current OS Build and click Next.
After downloading, run and install the .msi then Restart.
5: Run System File Checker Tool
See: Using System File Checker in Windows (microsoft.com)
6: Ensure Camera app is enabled
Open Windows Settings > Privacy
Go to Camera
Toggle the option under Camera for this device and Allow app to access your camera (make sure its ON)
Under Choose which apps can access your camera, ensure that the apps you want to use the camera is ON
7: Reset Camera app
Open Windows Settings > Apps > Apps & features
Locate and select Camera
Click Advanced options
Click the Reset button
If still the issue persist, please try to open Device Manager and expand System devices. Look for Intel Control Logic device. Right-click on the first entry if you have multiple entry of this driver then select Uninstall device (Note: Check the box for the Delete the driver software for device). Restart your Surface but if the issue persist, try uninstalling all Intel Control Logic then restart the Surface again.
Hope this helps.