Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
ex-pallesco, lŭi, 3, v. inch. n., to grow or turn very pale (perh. occurring only in the perf.): viden’ ut expalluit! Plaut. Curc. 2, 3, 32; Ov. M. 6, 602; Plin. Ep. 1, 5, 13; Luc. 1, 539 al.: erubuisse, expalluisse, titubasse … signa conscientiae sunt, Auct. Her. 2, 5, 8.
Poet., act., with acc.: Pindarici fontis qui non expalluit haustus, who feared not to drink, Hor. Ep. 1, 3, 10; Sil. 12, 146.