Messi currently has 50 goals in La Liga and another 11 goals in the Champions League, 2 goals in the Spanish Cup, 3 goals in the Spanish Supercup, 1 in the UEFA Super Cup and 2 in the Club World Cup.
Which makes 72 goals in total so far.

Messi didn't break Dean's record but he has broken a lot of other records:

 1. Most goals in one season in La Liga (previous held by Cristiano Ronaldo - 41 Goals in 2010-11)
 2. Best goalscorer in history in one season in Europe (previous held by Gerd Müller - 67 goals in 1972-73)
 3. Most goals in one season (previous held by Archie Stark - 70 goals in 1924-25)