Yes, smoking can lead to the dark circles under your eyes. Well, generally speaking, if you keep smoking, it actually does harm to your health, not only the eyes, but also the body organs. For example, by smoking, many people will have dark circles. It can be very serious. Anyway, in my opinion, you should give up smoking. And if you keep smoking weed, it will cause dark circles, because they are caused by a complex interaction between your body and the same kind of chemical reaction that produces bruises. For long term effects, it can lead to lazy eyes, and hearing loss. So maybe you should realize the serious point smoking has. And for your dark circles, you can take some measures to reduce them. For example, you can place cool cucumber slices over your eyes.
Well, you should understand that to some extent smoking weed is just like taking drug you know? Consequently, there are always some side effects which could be very serious and do tremendous harm to every part of your body, counting your eyes. So, my advice for you is to give them up, at least find some alternative to replace smoking weed.