Coke probably doesn't help. Try not to use any cocaine until the sore has healed?
How much coke are you doing? How is your nasal passage health generally, do you get nosebleeds ever, for example? Some people need to be more careful than others.
Also - what nose care guides are you following? Some are more sensible than others - for one, don't use tap water to irrigate your nose, it just dries things up further and there's a very tiny chance you can catch a brain eating bacteria from it. Use boiled (and then cooled!) water or sterile saline, a spray is very convenient but some people are into netti pots.