Front camera on iPhone 7 plus doesn't work, but back camera does.

I cracked my phone screen a little while back, and it has progressively gotten worse. The front camera doesn't work at all, just shows black in the camera app. However, the rear camera works perfectly fine. The speaker on the front does work, as well. This is the part that makes me wary. The screen is shattered in the top half to the point where you can see the front camera fully. Part of the LCD is broken and black, but the digitizer is fully functional. I plan to buy a replacement screen, but was wondering whether I should buy one with the front camera, or if this issue could be caused by something else, such as a broken piece on the motherboard? I want to get this phone back to working well, but don't wanna buy a screen with a camera included if that isn't the issue. Anything helpful on this would be greatly appreciated!