Nintendo Switch OLED low volume after opened it

I have a Switch Oled that I opened its plastic back to clean up some lint that got stuck in a tiny gap of one of the Joy-con rails. The problem is that after I put everything back on, the volume is much lower than before I had opened it. I'm confused because it was just the plastic back that I opened and I don't remember disconnecting any internal cables. The sound come out from both speakers just fine but with a lower volume. Is there any cable near the rail or edges of the device that I'm not aware of? Thank you.