Whatever was ailing Steven Tyler that caused Aerosmith to abruptly cancel the remainder of a South American tour, he’s still not saying. But it appears he’s fully recovered. The 69-year-old frontman, who raced back to Boston to get medical treatment after an Aerosmith show in Brazil in September, is once again performing. Over the weekend, Tyler was at the Tobin Center for the Performing Arts in San Antonio, singing a slew of Aerosmith classics to benefit the Tobin Center’s Generation NEXT Education Initiative. (Ten days before that, Tyler took the stage at the Rogers Arena in Vancouver to sing three songs — “Dream On,” “Cryin’ ” and “I Don’t Want to Miss a Thing” — at a benefit for the David Foster Foundation, which helps Canadian children in need of organ transplants.) Tyler was back in Boston Sunday night, dining with his girlfriend Aimee Preston at Regina Pizzeria in the North End.