Small and Seasonal Business Relief Act This bill amends the Immigration and Nationality Act to exempt returning workers from the nonimmigrant H-2B visa (temporary nonagricultural services) annual numerical limitations: (1) through FY2018 for those individuals already counted toward such limitation in FY2016 or FY2017, and (2) during the next fiscal year for those individuals already counted toward such limitation in FY2018 or FY2019. Such amendment shall take effect as if enacted on October 1, 2017.