How can one get rid of the habit of lying about academic grades, especially after repeated lying by inflating grades and being unable to apologize after the second lie?

Lying is a heinous sin and a blameworthy characteristic. Its prohibition and severe warning regarding it have been established. Lying leads to depravity and deviation from righteousness, and whoever habituates it is recorded as a liar with Allah. The liar must abandon lying and repent to Allah, and strive against their self to be truthful. You do not have to apologize to your friend if your lie did not cause her any harm.