After replacing touchscreen, horizontal black lines on lower LCD?

My daughter's 3DS touchscreen was not working correctly, so I bought a replacement digitizer and replaced it. Everything seemed to work well, and the touchscreen is now fully functional, but I believe I must have put something back together incorrectly as now there are a few black lines across the lower screen. I'm happy to take it apart again, but if anyone has suggestions for which connection would be the issue, and what might cause this, I'd really appreciate the help !

Thanks!