His jaw still wired shut from the beating he took, John Ayer, the man who won the acclaim of Miami by rescuing a young woman from a menacing mob, left the hospital to the applause of dozens of well-wishers.

During his hospital stay, Ayer, 34, received a call from President Reagan praising him for his bravery.

Ayer's father listened in on the call because his son could not talk, his jaw having been broken in two places. Several of his teeth also were knocked out and he suffered cuts and bruises from repeated blows.

Ayer, who operates his own home repair service, became an instant hero in crime-weary Miami this week after he saved the life of 19-year-old Patricia Vivier.

Late Saturday night, Vivier, a clerk, was driving home from work on a dark road in a low-income area of south Dade County, when another vehicle hit her car.

When she tried to restart her stalled auto, police said, between 50 and 100 men gathered and began terrorizing her. When Ayer saw what was happening, he stop his van, walked through the crowd and told Vivier to follow him.

When they were 100 feet from his van, both were attacked. After being repeatedly struck, they escaped when a motorist honked and startled their assailants.