Does repentance from sins that invalidate good deeds – such as boasting or showing off – restore the reward for the deeds that were invalidated because of them?

Sincere repentance eradicates the effect of sins and restores the reward of good deeds that were nullified by the sin. The one who repents from sin is like one who has no sin.

Apostasy does not nullify deeds except by dying upon it, according to some scholars. As for evil deeds, if sincere repentance overcomes them, it burns them away and restores the reward of good deeds that were nullified.

So, if a servant repents with sincere repentance, the effect of their sin disappears, and the reward of their good deeds remains for them.

As for showing off (riyaa'), if it mixes with a deed, it nullifies that deed to the extent of its mixture. If the one who shows off repents, the sin is removed from them, and the reward of their correct deed remains for them.