They can be used interchangeably, depending on the context.
repercussion - something usually bad or unpleasant that happens as a result of an action, statement, etc., and that usually affects people for a long time — usually plural
We didn't expect the decision to have such serious/enormous/tremendous repercussions. [=consequences]
consequence - something that happens as a result of a particular action or set of conditions [Can be positive or negative.]
The slightest error can have serious consequences. (negative)
One of the best consequences of lifting weights is building muscles. (positive)