After a really good prayer or a night of worship I feel a quiet glow of self-admiration. Has my pride wiped out the reward?
That quiet glow after a good prayer is not the enemy you take it to be. More often it is the natural sweetness Allah places in the heart of the worshipper, a taste of nearness. The soul has stood before its Lord and comes away warm, the way a face is warm after sitting in sunlight. Feeling joy in worship is no crime.
But there is a slender line between rejoicing in Allah’s gift and quietly crediting the gift to yourself, and you are right to watch for it. The Qur’an lays a hand on exactly this tendency.
“So do not claim purity for yourselves; He knows best who is truly righteous.”
Qur’an, An-Najm 53:32 · meaning
Notice what the verse does and does not do. It does not scold you for feeling good. It asks you to leave the final verdict where it belongs, with the One who sees the whole heart. So when the glow arises, turn it the way you would turn a mirror, so that instead of reflecting your own face it reflects His grace: “O Allah, this was from You, and only by You.” In that small turning, admiration becomes gratitude, and the same warmth is worship again.
As for whether pride has wiped out the reward, go slowly here. A passing flicker of self-admiration that you notice and dislike is not the settled arrogance the Prophet warned about.
“None shall enter Paradise who has in his heart an atom’s weight of pride.”
The Prophet (peace be upon him), Sahih Muslim (91a) · meaning
That weighty word speaks of a pride that has taken root and made a home, the pride that looks down on people and refuses the truth. What you describe is close to the opposite, for you are guarding your heart against that very thing. A flicker met with unease is a servant’s alarm bell working exactly as it should. The sin is not in the glow arriving; it is in holding it to the chest and feeding it.
So do not let this fear take from you the fruit of a good night. The reward rests with a Lord more generous than we can picture, and He is not waiting for a spotless heart but for a returning one. Each time the glow tips toward the self, tip it back toward Him. In time that becomes a habit: the sweetness stays, and the danger quietly withers.
One small step: After your next good prayer, before you rise from the mat, whisper one sentence returning the credit: “O Allah, this was Your gift, not my achievement.”