The Spanish champions qualified for the last 16 after a 3-1 win, with Messi scoring twice to end his recent goal drought.
"I'm calm about the recuperation from injury," he told UEFA.com. "I'm getting my rhythm back bit by bit and I think it really helps to have 90 minutes, then another 90, back to back so I can gradually re-establish the tempo and the form I had before the injury.
"It just helps physically. This time there have been two injuries really close together and that kind of impact you do notice. But I'm definitely getting past it and I'm happy with my form."
Barcelona are next in action when they visit Real Betis in La Liga on Sunday.