I am tested covid positive on 6 april and tested negative on 21 april and after that on22,23,24,25,26,27 i visited covid hospital for update of condition of my covid positive friend when i visted hospital i used mask can i get covid again in a week?

If we assume you now have antibodies and you wear a mask, it is unlikely you will get it again.

It is unlikely, but if you develop any flu like symptoms, please re test. Monitor your temperature and avoid contact with others as much as possible during the pandemic. Discuss a plasma donation with your local center if they are banking plasma from recovered COVID 19 patients.