Does changing a word in a Quranic verse during an exam due to not remembering it—for fear of failing—constitute a distortion that expels the student from Islam?

If one errs in reciting a surah or forgets part of it during prayer, they should try to correct the mistake or recall what was forgotten. If unable to do so, they may skip the verse or abandon the surah and begin another. As for intentionally adding something that is not part of the Qur'an, whether in prayer or otherwise, it is absolutely forbidden. Scholars have explicitly stated that whoever omits a letter from the Qur'an, or replaces it with another letter, or adds a letter to it, has committed an act of disbelief (kufr). Muslims are unanimous that the Qur'an is the word of Allah and His revealed inspiration, and that everything in it is true. Therefore, whoever intentionally omits a letter from it, or alters it, or adds a letter to it that is not included in the agreed-upon Mushaf, while intending all of this, is a disbeliever. The Qur'an is the miraculous word of Allah, revealed to His Messenger, peace be upon him, and transmitted through continuous, successive narration (tawatur). Thus, intentionally mispronouncing it (لحن) is forbidden, regardless of whether it changes the meaning or not, because its words are divinely fixed (توقيفية) and have been transmitted through tawatur. It is therefore impermissible to change any of its words by altering the diacritics (إعراب) or letters. Hence, it is not permissible for the student to write a word or a letter that they know is not from the Qur'an. Rather, they should strive to remember or leave the place of the forgotten part blank, and they can excuse themselves by stating that they forgot the location of the word.