No earpiece speaker and no proximity sensor after display replacing

Hello,

on my iPhone 8+ I replaced the display with a refurbished one. Everything with the display and the home button is fine, but the earpiece speaker and the proximity sensor is not working.

What happened is, that I forgot to swap that small black rubber sticker to the new display. Even after doing that, the earpiece/prox sensor is still not working.

What can I do? Will changing the flex cable with the sensor/front camera and changing the speaker solve that problem or is there another damage?

Thanks in advance

Marc