וַיֹּאמַ֗ר אָנָּ֤ה יְהוָה֙ זְכָר־נָ֞א אֵ֣ת אֲשֶׁ֧ר הִתְהַלַּ֣כְתִּי לְפָנֶ֗יךָ בֶּֽאֱמֶת֙ וּבְלֵ֣ב שָׁלֵ֔ם וְהַטּ֥וֹב בְּעֵינֶ֖יךָ עָשִׂ֑יתִי וַיֵּ֥בְךְּ חִזְקִיָּ֖הוּ בְּכִ֥י גָדֽוֹל׃ (ס)
At sinabi niya: “Pakiusap, O Walang-Hanggan, alalahanin Mo kung paano ako lumakad sa harap Mo nang may katapatan at nang buong puso, at ginawa ko ang mabuti sa Iyong paningin.” At umiyak si Hezekias nang labis na pag-iyak.
Rashi
AND HE HID THE BOOK OF REMEDIES. As it is written (II Kings 20:3; Isa. 38:3), "I have done what is pleasing (and righteous) to You." And we said in B'rachot that he hid the Book of Remedies because their minds were not subdued by the illness; instead, they would be healed instantly.