The word aftermath means consequences; especially, in current general use, ill consequences.
Also, which indicates the origin of the term, a second crop of hay after one crop has already been cut.
Math, a term no longer in use, meant “a mowing” in olden days, or the produce of a mowing; hay, that is. Thus an aftermath was a later or “after” mowing.
Used figuratively it meant later results or effects; consequences.