Brightness buttons don't work at all?

Ok so a mug of water (not much around 10-15ml) fell on my Mac and the when I turned it on (bad Idea I know) screen flicked on an off. I took it to a technician who fixed the flickering and told me to hook it up to a monitor with a vga cable. I have done that and nothing works on it. My mac screen is very dark but I can make out programs and they look like they all work. However my brightness will not turn up no matter what I do. Nothing will load onto the monitor either. I do not want to but a new mac but I need programs like final cut for work