Iphone 3gs back light problem.Advice needed please

Hi,

I accidentally put my Iphone 3gs into a damp pocket and now the screen is very dark. I dried the phone out and everything now works normally except the screen which is still very dark. I tried adjusting the brightness settings and this has no effect. I did some research and found that the problem was probably the back light and bought a new 6R8 coil and IC109b chip.

I replaced the 6R8 coil and the IC109b chip but it hasn't worked. The terminal fell off the coil when soldering but i managed to attach it to the coil wire instead. When i did a continuity test afterwards it indicated that the coil was working fine. Unfortunately this hasn't made any difference though and the screen is still dark. I would appreciate some advice on what to do next. Would you replace the coil again or could it be the actual LCD screen? If i can fix it without spending too much i will, otherwise i will wait for the Iphone 5 which i believe comes out soon.

Thanks in advance

Jack