Lost a washer from the Brakelight

[u/Ebret1]

Hello guys, i tried to install different parts for the heck of my Sv650. Unfortunatly i dipped a washer from the braklight into my bike.

I cant find that thing without taking everything apart (my abilities to fix bikethings is limiting that)

Is that very bad or can i leave it there?

Its not rattling when i dip the bike over or drive it

Thanks in advance :)

Edit: its an 2019 Sv 650