The 35-year-old underwent knee surgery in the summer, but returned to action in the Catalan outfit's 0-0 draw with Osasuna on Saturday.
"These past few months have been difficult for me," Puyol told reporters at a press conference.
"I am happy with how I felt on the pitch but not with our result. Now we must rest, recover and start thinking about AC Milan."
The draw with Osasuna was the first time that Barcelona have dropped league points this season.