Hello J_brill,
That's a great question! Since you're not seeing any external cracks, you'll want to walk through the troubleshooting steps listed below to resolve any software or external related factors that may be causing this issue. You can also find these steps in the following article.
- "Remove any case, accessory, or film that might block the camera or that places a magnet near the camera.
- Test the camera by trying to take a photo.
- If the photo is blurry, clean the front or back camera lenses with a microfiber cloth. If you see dirt or debris inside the lens or if the camera lens appears to be misaligned or blocked, contact Apple Support for help with your iPhone, iPad, or iPod touch.
- Restart your iPhone, iPad, or iPod touch.
- Test the camera again by taking a photo. If your device has a front and rear camera, check if one or both isn't working. To switch cameras, tap the rotate button."
If the camera or flash on your iPhone, iPad, or iPod touch isn't working
If you continue to have issues after completing those steps, contacting Apple is the right next step. You can find their contact details via the following link.
Contact - Official Apple Support
In reference to repair cost, the link below provides information service options and repair pricing.
iPhone Repair - Official Apple Support
Take care!