Water damage disappears after a year? Screen somehow back to life.

My apologies for the odd title - I'm not quite sure how to explain it in that space. I confess I just posted an identical thread on MacRumors; I hope you don't mind. I thought the question perhaps a bit better suited to this site.

I own a 13" 2009 MacBook Pro that I rather stupidly spilled a drink on on the 7th September last year. I turned it off when that happened but then turned it on not long after, which led to a sort of shock and, since then, it has worked just as before except for the screen. I've had to use it with a monitor or TV via HDMI. As a student, I'm lucky that the place I rented last year had an HDTV as otherwise I would have been unable to use my computer.

Two days ago, however, I turned on the computer and the internal display came on after a second of blue flickering. After shut down, the screen was again dead as before upon booting. This was the first time the display had worked since last summer.

Last night, the same thing happened - though when I rebooted into Boot Camp, the display disappeared. Again, after turning off the computer, the display did not turn on upon further start ups.

This morning, I just turned on the computer and the display has again booted. There was just a blue flicker again but otherwise the display seems to be working. I'm fairly certain, though, that when I shut down or perhaps even put my computer to sleep the display will not come on.

Does anyone know what might be causing this? I had assumed that my turning on the computer while wet had caused a shock that burnt out the display connector but somehow, a year later, it seems to be working again if only occasionally.

If there is some way I might ensure the display working, it would be invaluable.

Thank you very much for reading.