The five-time Ballon d'Or winner announced he would make himself unavailable to the national team after their penalty shoot-out loss to Chile in the Copa America Centenario final in 2016.
It was the fourth time Messi had missed out on glory at the last hurdle with Argentina, the Copa America having previously escaped his grasp in 2007 and 2015, and Germany beating them to the World Cup in Brazil in 2014.
Head coach Gerardo Martino was replaced by Edgardo Bauza after the failure in the United States, and he successfully convinced the Barca forward to return to the fold despite some initial concerns.
"It was a decision I made in the heat of the moment, but I was embarrassed to say I wanted to come back," Messi told DIRECTV Sports.
"El Paton [Bauza] and my team-mates made everything easier for me to return."
When donning the Albiceleste shirt, Messi carries the weight of a nation desperate for him to bring an end to a trophy drought that has stretched for 24 years.
The Argentina captain shares a difficult relationship with supporters in his homeland, but age has helped him cope with the expectation levels.
"At 30 years old, I enjoy it in a different way and much more than before," he said.
"I take advantage of every moment, both on and off the pitch. I am experiencing this moment with the national team in a different way.
"I am more relaxed today. When they criticise me, I experience it differently."