There are certain narrations that say whenever you place out your hands and supplicate to Almighty God, when you finish you should wipe your face and head with your hands.
I have come across a tradition that says the reason for this is because angels receive the dua from your palms.
However, when it comes to Qunut, in your daily Wajib prayers, some Fuqaha deem it as makruh, and therefore it is best not to wife your face with your hands after Qunut, in faridhah prayers.
There is a recommendation for you to do this in Nafilah prayers.
Please refer to the view of your Marja' taqleed.
And Allah knows best.