How long does it take for orchitis to disappear?

It depends: It depends on the severity of the orchitis and how quickly antibiotic therapy is initiated. I would estimate 3-7 days.

Here are some ...: If Dx is correct and antibiotics is effective, you should feel better in 1-2 days and gradually resolve to almost no pain in 5-7 days, but the testicular induration and tenderness may linger for weeks or months with a wide variation among the infected men. But still remember some orchitis is not bacteria-related. More detail? Ask Doc timely.