Can I fix backlight?

Bought this iPhone second-hand with some damage already to the case, and the power button almost never has worked.

In the past week or so, the iPhone got in shallow water for a little while, and possibly got a bit of water damage. For just a bit (while it hadn't finished drying out??), the power button worked. BUT, the backlight hasn't worked at all ever since.

I've opened it and looked around and cleaned up a lot of dust in the corners (the chrome and black back have a crack between them). But the little "dots" are still white and I can't discern any water damage anywhere. Connections for 1, 2 and 3 are all very clean.

I also tried wiping it clean and restoring from backup just to be sure a hard-reset-type action would fix it....

Nothing has changed.

It doesn't seem to me that there is any clear-cut part I could replace to fix that -- is that correct? Or is there??

Thanks!

PS: Don't forget - the power button doesn't work, so I can't do a hard reset, etc.