Does "mascarillas" make a difference?

The politicians in Spain have put extreme emphasis on the use of face masks ("mascarillas") among the public to curb the COVID-19 pandemic. This stand in strong contrast to Sweden, where hardly no one have been wearing face masks ("mascarillas"), neither indoors or outdoors.

One could expect that there would be a big difference in the infection rate between the two countries, but this is not the case.