i just answered your question on the other post, but here it is again
you will be able to feel it right away. if you have that hole you should be able to stick one finger in one nostril and out the other, yes that's gross, but that is how you tell. i damaged my septum also. are you still using coke? you can definately feel the hole, but it will just keep getting bigger as long as you use. trust me, you don't want to damage your septum, it is very painful and bloody as hell.
as giz said you will feel the hole, unless it is very early and still small. do you experience unexpected nose bleeds? sinus problems like stuffy head, etc? sometimes the nose will actually bleed down the back of your throat instead of out your nose. means the hole is actually higher up in sinus cavity. i would say if ya think ya got one, c an ear nose throat doc. it is not something to mess around with, it hurts and doesnt grow back. good luck, oh and quit snorting coke LOL