I reckon it's not the cocaine that you have to worry about; it's the dirty horrible stuff that it's cut with. Likely problems are cancer, blocked or thinner arteries, increased risk of heart and stroke etc. I've also heard that ammonia can cause coughs and be very irritant to your lungs so if it's got ammonia in it you'll toil to run a marathon next day.
you cant damage your lungs through snorting cocaine as the substance is inhaled, which means the the way cocaine gets into your blood stream is through the mucous membranes in your nose. It is absorbed through the skin then int the tiny blood vessels. which then carry the substance into your blood stream, your brain and heart.
If you smoked/ piped crack cocaine. then of course it goes via your lungs which can result in damage.
Ps i am a drugs worker for a drug project in London-so i know my stuff!!