Start by resetting the NVRAM and SMC. If that doesn't help, then you know you have a hardware issue with the display. Replacing the camera itself on these models is not easily done. You would need to fully disassemble the display assembly and do some very delicate microsoldering. The more feasible approach is to replace the display assembly, but the displays on these can be pretty expensive. Here's a [link|https://www.ebay.com/itm/166728677776?chn=ps&var=466373312918&_trkparms=ispr%3D1&amdata=enc%3A1OFngeVbCRm-fmnYn0vxrPA49&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&mkscid=101&itemid=466373312918_166728677776&targetid=2320093655185&device=c&mktype=pla&googleloc=9033026&poi=&campaignid=21222258394&mkgroupid=164713660992&rlsatarget=pla-2320093655185&abcId=9408285&merchantid=421393343&gad_source=1&gbraid=0AAAAAD_QDh_YZhOr0bCSo0bDztxtZoM4T&gclid=Cj0KCQjwveK4BhD4ARIsAKy6pMK8BF7S7SR7RnYO4hCeZ_znX2p1R-cQTDTDe-R3dYhYxlcooIMiW_kaAnRPEALw_wcB|link] to a display. Good luck!