Consequence and repercussion both refer to results, but they are not used in exactly the same way.
Consequence is the broader word. It can be neutral, good, or bad, depending on context. It simply means the result of an action, decision, or event.
- Missing class had consequences.
- Studying hard can have positive consequences.
Repercussion is usually narrower and more negative. It often suggests an unintended bad effect, especially one that follows a decision or mistake.
- The company faced legal repercussions after the safety violation.
- His rude comment had social repercussions.
A helpful contrast is this: every repercussion is a kind of consequence, but not every consequence is a repercussion. If you want a general word for any result, use consequence. If you want to emphasize harmful aftereffects, use repercussion.
In everyday writing, choosing the right word makes your meaning clearer. Use consequence for broad results, and repercussion when the result is negative and often indirect.