Water leak in rear panel

[gm94]

Hi its gm94 again buging you all again lol! I just pulled out the spare tire to check it and i noticed some water at the bottom of the area. It has a small hole that i'm not if it is a drain. I put a rubber plug in it but i noticed that the water is dripping also from the top against the side of the panel. I put a napking and rub it on the edges just to make sure and it was moist. Anyone had any problems with leaks in this area? Any places to start looking? I don't see any cracks but im going to remove the whole side panel cover to see if i can find it. Any suggestions are greatly appreciated.