One pap smear said it was bv then another months later said it was trich. could he of just been wrong the first time?

Paps & infection Dx.: Pap smears are very helpful in providing a preliminary identification of a potential vaginal infection. However, it is often necessary to do further testing like a wet prep(smear) to view the offending organism under the microscope to provide a conclusive diagnosis. In your case, you could also have acquired the trichomonas infection separately after the first was properly treated. See a GYN MD