When exactly did voldemort lose his nose?

When Voldemort killed the Potters, he still had his original body, that of Tom Riddle, and though his looks would have been distorted then because of the creation of his Horcruxes, he would still have had a nose at that time and would not be as snake-like. He lost his original body when he tried to kill Harry and the curse rebounded on him.

The body he has now, with the snake-like features, and as everone is so focused onn, lack of nose, was created later through a potion and looks the way it does because it was magically synthesized. It is likely as snake-like as it is because Voldemort fed on snake venom, and largely incorporated his snake in the task of building himself a new body.

Um...yeah...he was a normal looking guy.

voldemort did have a nose when harry was a baby.

After he killed Lily. My question is how did he lose it?

Google it.

at the end of the goblet of fire

I believe that Voldemort was relatively normal in appearance when the curse rebounded on him after he killed James and Lily. It is said that he was living on unicorn blood and snake venom, and was living a cursed half life. The Unicorn blood was to sustain him until he could regain his corporeal form.

When he was reborn and returned I believe he assumed his true outward appearance, which matched his inner self, which of course was pure evil.

It is unclear exactly when these changes began. However, my extensive research into Voldemort's life allowed me to pinpoint a likely time frame.

Tom, in his last couple years at Hogwarts, looked quite handsome. At the time, he was still researching the idea of Horcruxes and formulating his plan.
When he returned to the school, inquiring about the vacant DADA post, it was said his features were blurred. At this point, around the age of eighteen, we can assume Vvoldemort's face became snakelike.
It can be assumed that he had at least one Horcrux the night he returned for a job. Of course, the job application was mainly a ruse to allow him to search the castle for an object to make into a Horcrux.

Because he sank into the Dark Arts and Horcruxes