וַיְהִ֞י אַחֲרֵ֣י ׀ הֵסַ֣בּוּ אֹת֗וֹ וַתְּהִ֨י יַד־יְהוָ֤ה ׀ בָּעִיר֙ מְהוּמָה֙ גְּדוֹלָ֣ה מְאֹ֔ד וַיַּךְ֙ אֶת־אַנְשֵׁ֣י הָעִ֔יר מִקָּטֹ֖ן וְעַד־גָּד֑וֹל וַיִּשָּׂתְר֥וּ לָהֶ֖ם עפלים [טְחֹרִֽים׃]
Pagkatapos nilang ilipat ito, ang kamay ng Walang-Hanggan ay laban sa lungsod, at nagkaroon ng napakalaking kaguluhan. Pinahirapan niya ang mga tao sa lungsod, mula sa bata hanggang sa matanda, at nagkaroon sila ng almoranas sa loob ng kanilang katawan.
Rashi
And they were afflicted internally.וַיִשָֹּתְרוּ is identical with וַיִסָּתְרוּ for it is listed in the Masora among those words written with a 'שֹ' and explained as though it were written with a 'ס' meaning "there was a plague in the hidden parts of the body."2Or it may mean that the plague occurred at night when it was dark and they were unable to see the שְׁרָצִים, i.e., the plague was hidden from them.—Da’as Sofrim