What is the correct cocaine snorting technique?

I wanted to ask if I should be worried about itchy nose after using cocaine.

At the time of snorting I had some nose bleed. It stopped fairly quickly within half an hour. Since then only once I had some blood coming out on a tissue but just once, two days after my first cocaine intake. Then, 5 days after the first intake I snorted again the same shit. But this time I didn’t have any nose bleeding.

However, since then I have felt my nose fragile and sort of itchy. In the last few days it has become increasingly itchy and I would say it even hurts a tiny bit. No bleeding, however. I have also been sneezing a lot and having runny nose for the last two days, sort of flu symptoms.

Timespan:
1st snort 14th of Feb (with bleeding). Second bleeding 16 Feb.
2nd snort 18th Feb (no bleeding)
27th Feb until now – increased itchy-ness and flu sympthoms like sneezing, feeling down, runny nose (not sure if actual flu or just the nose)

Unfortunately, it wasn’t the purest of cocaine… Do you think I should be worried?