Does a small sip of water from one's face during prayer invalidate the prayer?

If the prayer is supererogatory (nafilah), it is not invalidated by a small, intentional drink. However, if it is an obligatory prayer (fard), it is invalidated by a small drink, unless it was due to ignorance or forgetfulness, in which case the prayer is not invalidated. It is inconceivable for a person to drink a large amount of water from their face. One must be cautious of obsessive whispering (waswasah).