Smokin in back

I noticed that I have smoke commin out of my exhaust. I noticed this after I changed my oil. I'm not sure if it was doing it before. I also see some liquid in the exhaust tip. I think its burning the liquid to smoke but I didn't wash it or anything. Any ideas on what this is? is it something I need to worry about or not?

thats probably unburned gas, caused by a spark plug wire not firing. or could be coolant, check your spark plug wells and see if you have any corrosion in there.

the liquid could also be just water moisture. What color is the smoke? black? white?