Assalaamu alaykum. If a person has been wiping his face as he knew it as a part of wiping the head (so he was wiping the face a fourth time), does it invalidate his ablution? He did not know that only the head had to be wiped. If it does invlidate the ablution, does he have to repeat all the prayers (obligatory and voluntary)? I was asked to resend this question; what i meant was that I washed my face thrice, then washed my two elbows thrice, then wiped over my face and head, and then wiped my two ears. So overall, I washed my face four times, but I heard that if a person did not know a ruling, his previous prayers will be valid.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ʻalayhi wa sallam, is His slave and Messenger. 

It is not prescribed that you wipe your face when wiping over the head in ablution; however, this has no effect on the validity of the ablution or the prayer. Your past ablution and prayers are valid as long as you washed your face in the ablution, which you mentioned you did do.

Allaah knows best.