Looks like Taylor Swift has gone back to her older more wavy hair style
Most recently Taylor Swift went with a totally suicide blonde and seriously straight hair style (a look that would of maybe been a cool look for her next album), although she has already foregone it looks like. Taylor is now back to her previous wavy more natural color hairstyle all of a sudden. This leads might lead you to think that possibly the other hairstyle was a wig.
Taylor Swift did however post an Instagram picture of her an Karlie Kloss only days before these more recent photos, and she did appear to have straightened hair, although not bleach blonde hair. So the wig theory is probably not the best one, and it probably more accurate to say that Taylor got tired of the more modern alt kind of look and merely dyed her hair more of her natural color.