If the oxidation state of an element goes from -2 to -3, is this reduction or oxidation? similarly, if it goes from +3 to +2, is it reduction or oxidation? 

Dear student,
Since the oxidation state of both the element is decreasing from -2 to -3 and +3 to +2, the element is reduced by gaining some electrons to the oxidised atoms. Thus, the element undergoes reduction.
Regards