I am smoking 3-4 cigarettes a day and plan to have a neck lift in 5 days. How dangerous is this?

You should call your surgeon  immediately and let him or her know of the situation. Unfortunately for both of you, your surgery will likely have to be postponed. No surgeon, experienced or not, is going to perform any sort of elective cosmetic surgery on somebody smoking. My rule is one month off before and one month off after, at a minimum. Vaping is the same. Cameron Chesnut#RealSelf500 physician 

Thank you for sharing your question.  The effects of smoking on wound healing after surgery has been well documented on this website and I would strongly urge you to inform your surgeon of your cigarette use.  I would counsel you against surgery as at a minimum you will have poor healing incisions and at worst can sustain substantial skin loss.  Hope this helps.