why is my exhaust smoking?

I would say that is excessive oil consumption.A compression test may help,if any cylinder readings are low,squirt some oil into them,if they improve that could point to worn rings/pistons/bores.If valve stem seals are worn generally you will see blue smoke on the initial start up for a wee while,any matter the cyl.head will need removed for a more detailed examination and could be a costly exercise or a replacement engine would be another option.You will need to weigh up your decisions whether it is worth the expense or scrap the car.

cdc
October 2013