I had a poster that I presented at a regional meeting, that was later presented at a national meeting. I just listed the national meeting presentation on ERAS and made a note of any awards I received at the regional meeting in the honors/awards section. Though when I attended conferences that also published the abstracts, I dual listed (one peer-reviewed abstract entry and one presentation entry).
That being said, I think there are some benefits to presenting at multiple conferences (especially if you can find somebody to fund most of your travels -- some meetings will offer student scholarships and student affairs and pertinent departments at the medical school will often help you out). For one, you receive a lot of constructive feedback re: how to improve your presentation and identify weaknesses in your project to further improve and strengthen your manuscript. Secondly, if you happen to win awards at multiple conferences, those are definitely list-able on your CV/ERAS. Presenting the same thing at more than two meetings is probably overkill, though (but if the abstract has already been accepted to multiple meetings, some societies may frown upon withdrawing).