If one remembers after the prayer that he did not wipe his head

Question:
Honorable Shaykh! A man prayed the 'Asr prayer, and after the prayer he remembered that he had not wiped his head, and this is certain, not a doubt. What should he do?

Answer:
If he repented because he did not wipe his head, he must renew his ablution and repeat the prayer. However, if it is merely a doubt after the prayer, he should not act on it. If it is merely a doubt after the prayer, or even after the ablution, such that he has finished his ablution and doubts whether he wiped his head or not, he says: I do not doubt after I have finished, after the count. But if the believer [is certain], he takes water and wipes, then he repeats the ablution and repeats the prayer. Yes.