Hey Theroux, I'm not sure I can answer your questions about the physical health risks regarding the regime you're trying out. Recently, I also tried to follow a similar regimen of very occasional, low dosage cocaine use.
I started doing this because I felt that it helped me study better. I would use cocaine later in the evening to give myself a boost, and then it would wear off by the time I needed to go to bed. It worked much better than Adderall, because it didn't last nearly as long. And I don't really have a supply for Ritalin right now, but in the past I've found that Ritalin will also keep me up at night.
Unfortunately, recently I have become rather lax in my personal discipline, and this is my warning to you. Cocaine is an addictive drug, and for me it becomes too easy to start justifying why I need to take 'just a little bit more.' A big problem with psychological addiction is that you might not even recognize that you're slipping into it, and it becomes easier and easier to justify doing more coke and doing coke at times that aren't necessarily appropriate. Times that when you first started your regimen you would never have done coke in those circumstances.
Another important thing to point out is that everyone responds differently to different chemicals. I know from my family history and my own personal history that I have a tendency towards over-using drugs. Currently, this is very apparent with my alcohol consumption, as well as my use of Benzos to help fall asleep at night. These are issues that I am working on and that I am confident I will overcome, but everyone is different. For several years I was a daily (all day) weed smoker, but I have successfully managed to control that over-use so that now I only smoke weed on very rare occasions.
As far as my personal cocaine use, I am hoping to extend the ~1.75 grams of coke that I have for the next 2 days to help me be productive with my studying. I also have about 0.25 g dissolved in a nasal spray that I intend to use during the exam I have this coming week. After that, I plan on not buying any more coke, as I feel that I do not have enough will power to use it in the way I originally intended to use it. Honestly though, I'm even worried about this plan, as it is sooo easy to buy coke over the dark net and just have it shipped to your door.
So good luck with your usage man! And watch out for the subtle, creeping signs of over-use. Full blown cocaine addiction is not something that anybody wants, and so you need to be very vigilant about your own use.
If I had to take a wild guess to answer what your original question was, I would say that binging every once in a while might actually be better for your nose than regularly taking small doses. Cocaine can damage your nose by temporarily restricting blood supply, by forming a small amount of acid (HCl) when it gets absorbed, and by causing unforeseen damage from any of the random crap the blow is almost always cut with. The main tissue you should be worried about is the cartilage tissue (particularly in the septum) as this is the least likely to heal from damage, but it is my (unprofessional) understanding that this would require a lot of cocaine use in order for the damage to be noticeable. With regular small doses, you're decreasing the blood supply (through vasoconstriction) to your nose and nasal pharynx on a regular basis, which might decrease the tissue's ability to repair itself and fight off infection. An occasional binge will also decrease blood supply, but blood flow will return to normal once the drug wears off and you will (hopefully) have a greater time between binges for adequate blood supply to keep your nose/nasal passages/nasal pharynx healthy and repaired. That being said, taking a month off between use will definitely give your tissues time to heal, but I honestly don't know the true answer to your question.