The fact that Face ID still works but the front camera doesn't is an important clue. Face ID uses a separate infrared/dot projector system within the TrueDepth camera assembly, while the visible-light front camera sensor is a distinct component. This means the Face ID hardware is intact but the main front camera may have failed.
Try these steps before concluding it's hardware:
1. Restart your iPhone:
- Press and hold the side button + volume down, slide to power off, then turn back on
2. Check Camera permissions:
- Settings > Privacy & Security > Camera
- Make sure Camera access is enabled for all apps you are trying to use
3. Force-quit and relaunch Camera:
- Swipe up to the app switcher, swipe away Camera, then reopen it
4. Reset All Settings (does not delete your data):
- Settings > General > Transfer or Reset iPhone > Reset > Reset All Settings
- This resets system configurations that may be blocking camera access
5. Update iOS:
- Settings > General > Software Update and install any pending updates
If none of the above work, this is very likely a hardware failure of the front camera sensor. This can happen from a drop, pressure, or moisture even without visible damage. Since Face ID still functions, the TrueDepth dot projector is fine, but the main camera chip or its flex cable connection may have failed.
In this case, contact Apple Support or visit an Apple Store/authorized service provider for a front camera repair. If your iPhone 13 mini is still within its 1-year warranty period, the repair may be free.