Need help to resolve issues after water ingress

Hi all, great web site. It inspired me to try and fix my phone after it was soaked in water while riding my bike home on a rainy day. I came to the obvious conclusion that my warranty is void and i didn't have insurance. So i pulled the rear cover off and dried the phone out in front of a slow heater fan. I noticed the lower water dot was pink and the upper one was still white. With this in mind i was positive it was going to be ok. I did find water within the connector of the logic board and the battery connection. So i let these dry. Curiosity got the better of me and i pulled the logic board, microphone parts out to ensure there was no more water laying around. The battery took some persistence to remove but was ok. So after re-essembling the phone wouldn't turn on. I did lose the 2.4 screw to the microphone/speaker unit so have replaced with the 2.4 screw that was under the water dot. it doesnt seem to need a screw there. I have tried plugging into power and leaving but still no joy. it isnt recognised by itunes at all. So reading the posts on this site I presume my next step is to try a new battery but im not sure where to go from there. Could the missing screw mid way on the logic board cause any miss-behaviour. Look forward to hearing from you..