Hi Nelly, and thanks for your post. You've posed an excellent question! There have been many in our community who have expressed similar issues when it comes to using nasal cannulas/oxygen tubing so, you are not alone.
We actually have a wealth of published material (right here on COPD.net), which focuses on pretty much every aspect of this subject. For your convenience, here is a link to several of those articles: https://copd.net/search?s=nasal%20cannula%20irritation.
I realize it is a lot of information. Please don't feel you have to read it all! I thought you could keep the articles handy to read some now, and have the rest for reference should you need them.
Wishing you well,
Leon (site moderator COPD.net)