Face buttons not working (Square, X, Circle, Triangle)

Hi! I recently opened up my controller to replace the micro-USB port (worked swimmingly!), but now a few buttons aren't working. As said in the title, the face buttons (square, x, circle and triangle) all aren't working. Additionally, the PS button isn't working. All other buttons are looking fine. I opened it up and checked the membrane-type thing to see if it looked weird, or anything that might be stopping it from registering inputs, but it seems fine. Any ideas for any troubleshooting to get these buttons working again? Thanks.