Why is Voldemort's face so deformed?

once he started loosing his soul to the dark arts and horcrux making- it made him less human. i think the uncanny relationship between himself and snakes (nagini and others) made him more snake like. in GoF he revels that he possesed snakes (which didn't last long after possession) to keep himself alive. as a boy, riddle was exceptionally handsome. but in HBP, harry notes his appearance in dumbledores office (when LV applied for the job,) to have lost that quality. he had defiantly changed from when he had his job at borgin and burks to that meeting, leading me to believe he creating at least 1 horcrux in that time period. hope this helps a bit.