Barca have seen leads pegged back in consecutive matches this week.
Valdes said: "It was not a result we liked and the draw certainly came as a disappointment.
"We need to learn and even more so in dead-ball situations. We have to analyse and learn from our mistakes and make sure they don't happen again.
"We need to pick ourselves up quickly because we have a league match to come [against Osasuna on Saturday]. This has only just started."