Ace Ventura is a Miami private investigator who specializes in the retrieval of tamed or captive animals. Despite the occasional successes, he struggles to pay rent and repair his battered 1970s Chevrolet Monte Carlo. He keeps dozens of different animal in his apartment, and his eccentricities make him the laughing stock of the Miami-Dade Police Department.
Two weeks before the Miami Dolphins football team is due to play in the Super Bowl, the team mascot, a bottlenose dolphin named Snowflake, is stolen. Besides notifying the police, Melissa Robinson, the team's Chief Publicist, also hires Ace to find Snowflake. Ace discovers a rare triangular-cut orange amber stone, which he speculates to be part of a 1984 AFC Championship Ring. Ace tracks down the players in the team photo and sees their ring, but is dismayed to find every ring intact.
Roger Podacter, Miami Dolphins' Head of Operations, mysteriously falls to his death from his apartment. At the crime scene, Miami Police Lieutenant Lois Einhorn concludes the death to be a suicide. However, Ace proves it was a murder, embarrassing and infuriating Einhorn. Ace learns of a former Dolphins player named Ray Finkle, who also owned a ring but did not appear in the team photo, as he was added later in the season. Finkle missed the field goal kick at the end of Super Bowl XVII, which cost the Dolphins the championship and ruined his career. Ace visits Finkle's parents and discovers that he blames Dan Marino for taking the snap incorrectly, causing him to miss the kick. Finkle became so obsessed with the loss and Marino that he became insane and was committed to a mental hospital. However, despite Ace warning Melissa to send extra protection, Marino is still kidnapped. Ace visits Einhorn and explains his theory: Finkle kidnapped Marino out of revenge due to blaming him for his career having failed. Also, he took offense to the Dolphins giving Snowflake his number and teaching it to kick a field goal, and presumes he killed Podactor after he found him snooping around. Einhorn compliments him on his finding, and tells him to let the police finish the job. Ace declines, saying it is his job to find Snowflake.
Ace and Robinson go to the mental hospital where Finkle was committed. Ace searches Finkle's belongings and discovers a newspaper article about a missing woman named Lois Einhorn. Studying this, Ace realizes that Lieutenant Lois Einhorn is, indeed, Ray Finkle. Soon after, Ace makes himself vomit and sets his clothes on fire, feeling disgusted that he made out with Finkle.
On Super Bowl Sunday, Ace follows Finkle to an abandoned yacht storage facility, where he finds Snowflake and Marino. Ace subdues Finkle's henchmen, but before he can rescue Marino, Finkle holds him at gunpoint. When the police arrive, Finkle claims that Ace is the kidnapper and orders them to shoot him. Ace strips Finkle and with a little help from Marino, exposes his true identity, as it turns out he didn't perform the penectomy and vaginoplasty to perfect the disguise. Podacter discovered this during an earlier rendezvous with Finkle, so Finkle murdered him. Finkle attempts to kill Ace, but Ace subdues him and takes off his ring, a 1984 AFC Championship ring missing a stone. Finkle is then arrested and charged with murder.
Marino and Snowflake return in time for the Super Bowl between the Miami Dolphins and Philadelphia Eagles. At halftime, Ventura sees an albino pigeon (worth a $25,000 reward), but Swoop, the Eagles' mascot, shoos it away before he can catch it. Enraged, Ventura beats the mascot while he is thanked on the JumboTron for saving Marino and Snowflake. Ventura briefly stops fighting Swoop and smiles as the audience cheers for him.

Question: Why did Ace make himself vomit and set his clothes on fire?
Answer: He made out with Ray Finkle 
Alternative answer: Because he made out with Finkle in disguise.