Without opening the case of your MacBook and taking a look inside it is impossible to know if the spilled liquid will cause you more trouble than the loss of the keyboard backlight. Any liquid entering an electronic device is likely to cause some havoc and the residue of any wine that might have made its way deeper into your MacBook's guts could cause corrosion and more trouble over time. If you are not feeling up to opening the case of your laptop to take a look, I do suggest you find someone to do it for you. The flow of electricity and any acidic wine residue will react with metal surfaces in internal connectors and just cause more problems. You may be lucky and the keyboard light is all that will go wrong. Depending on how much you are willing to risk you could just hope for the best and run with it, but not having someone look for more residue and letting it ride could make the computer a total loss. I'm not sure what the folks at the Apple Store would do. They might be willing to take a look, their official policy might be to turn you down but I have had a few pleasant and very helpful surprises at Apple Stores when I have had computer trouble on the road. They may have someone to recommend too.
To get a feel for what you would have to do to clean up the inside of your machine by yourself locate the disassembly guide for your particular MacBook here. For more about dealing with liquid spills have a look at the Electronics Water Damage page.
Unfortunately you are probably stuck with deciding if spending some money on prevention is worth it. I wish I could offer more than that. Good luck and I hope it works out.
If you are going to have someone take a look for you, do it soon and keep the computer off until then. The links above were suggested by ABCellars, many thanks!