A 19-year-old Carson City man was arrested Sunday evening, a day after he allegedly beat a 17-year-old Carson City man who was causing trouble at a party, leaving the teenager with a swollen head and face.According to a police report, Phillip Muckenstrum told a deputy that a friend of a friend with whom he was driving Saturday night asked for help in dealing with the 17-year-old, who had been drinking heavily. The beating victim had a blood-alcohol content of 0.31, according to the report.Muckenstrum and his friend drove to the house near Colorado Street, found the teenager and, after some …