I just have a quick question. when wiping the head in wudhu if a person accidentally wipes too far and one or more of his fingertips touch his forehead and thus the water of his fingertips mixes with the water of his forehead, does this make the wudhu invalid and in turn does he have to start his wudhu again or is it permissible to continue and wipe his feet with this hand.

He can wipe his feet with the rest of the hand