Hi Anne
it looks like you even removed the parts how where not really ment to be dissembled by customers.
(the T5 screws like @urs_lesse explained). the problem with watter damage like in the guide ✏ How to handle water damage
is mostly not visible, that’s the reason that indicators are pleased inside the phone, to tell if ther ever was watter inside.
@urs_lesse told that he directly removed the battery. like explaind in the guide that the only way to save the phone. if the phone was on or turn on wel wet it will have shorted the internal parts, not something wat will leaf visual marks, but it may kill the phone.
if you are lucky its only one of the replaceable parts that was shorted by the watter inside the phone.
about that picture, maybe clarify what small part you meaning.
i see a flat cable with a bord to bord connector on both sides completely loos from the phone.
yes that is a very important part of the phone.
please use the guide from i fixit it for information about how to disassemble and assemble the phone.
or the information on the Fairphone website.
i see a very small translucent yellow plestic thing on top of the bord to bord connector. i can 't tell where that is coming from. and i dont think it supposed to be between the connectors. but it will be a original part of your phone wat i can tell. probably to prevent the bord touching the metal frame.
i think you should consider bringing your phone to a telephone repair shop, water damage is even for professional phone repair shop very difficult to solve.
and sorry to tell, often not possible.