Water damage: display won't turn on after sleep.

Hello dear IFIXIT comrades,

I spilled a full glass of water on the back/right side of my MacBook while it was on, I had several peripherals and an external display plugged in, so I tried to unplug everything quickly and shut it down. It was only a few seconds but I guess some water got to the hinge and side vents as it flowed through my desk, once I was done unplugging and right before I clicked on "Shut down..." the built-in display started flashing (black/image/black/image).

I let it dry with the display open on the side/back switching angles a couple of times for a full day, I also used a blow drier just for a few minutes. Then I removed the bottom casing and let it dry out for a few more hours.

After a long and excruciating wait I turned it on... and it works perfectly! The first "OSX loading" progress bar was a little slow and got stuck, the display flashed for a few seconds (and I got really scared), but then it resumed loading and everything worked fine. After using it for a few days I noticed the following strange behavior:

- If I restart/shutdown the built-in display works perfectly, however after it goes to sleep it wont turn back on. It's all black, but has "light"(the apple logo on the back side lights up, the brightness adjustment keys work, and the display is not completely dead.. it's like it's projecting a totally black image).

- Everything works fine with the external display, so I turned on mirroring and that's how I'm using it as I type this right now.

So on to my questions:

1) Is there something I can try to fix this?

2) Should I take it to a professional? Do you think it's better to go to an Apple Store or just any repair shop? (specially in terms of $$$)

3) Can this get worse? Is it safe/ok to continue to use it with an external display?

Thanks!!!!