If I don't use an oral fungus med. For thrush will it away by it self evenally?

Oral thrush course . Presuming that the thrush was formally diagnosed, the recommended management for resolution, is identification and treatment of predisposing factors and antifungal therapy. Judicious oral hygiene is critical, but will not by itself resolve oral candidiasis.
Probably. Oral thrush is an overgrowth of the fungus you have in your mouth. Topical meds like Nystatin mouthwash is very effective at clearing it. If you do not use it, it will eventually clear with good oral hygiene and scraping your tongue with your tooth brush.