After water damage, no GPS and "No service"

Hi everybody, my 5s has been water-damaged. I left it in rice during 24 hours to absorb the water. When I turned it on, i remarked that the phone couldn't find his location, and it couldn't find the cellular network when far from the antennas. When I come close to an antenna, the phone finds the network but the signal is very weak. At first I didn't notice the GPS wasn't working, and I thought it was an antenna problem. So I changed the dock connector as the GSM antenna is located on it.

But now I think there is a problem in the top area of the phone, where the GPS seems to be. I also noted that the only water sensor that was triggered is the top one on the motherboard.

What would you advise me to do ? I think the top antenna doesn't work at all. How to solve this ?

Thanks !