I'm taking Selectra 10mg tablets, stomatitis is detected, can I use Mycoson or Levoryn together with tablets?

Yes, you can, especially if the medication is used as directed by your doctor. 

Mikozone is a topical cream so it does not interact directly with Selectra.

I do not find Levoryna in the List of Medicinal Products registered in Poland, so please clarify your question.

Also be aware that one of the side effects of Selectra is dry mouth, which may predispose you to inflammatory changes. I encourage you to report the symptoms you are experiencing to your doctor, as well as to report the occurrence of an adverse reaction of the preparation. Reporting side effects allows you to increase control over the medicines available on the market. We wrote more about how and why to report side effects in the article: 
https://www.gdziepolek.pl/artykuly/jak-i-dlaczego-zglaszac-dzialania-niepozadane

If you are concerned about this situation, it is always a good idea to consult a doctor who can give you more personalized advice. If you do not have the opportunity to take advantage of the advice, I am attaching a link to the online teleconsultation: https://www.gdziepolek.pl/telekonsultacja/z-psychiatra

We also encourage you to familiarize yourself with materials on similar topics: https://www.gdziepolek.pl/artykuly/czy-przyjmowanie-kilku-lekow-jednoczesnie-jest-bezpieczne

https://www.gdziepolek.pl/artykuly/czy-mozna-laczyc-leki-ze-soba