i accidentally liked my own post, can you not undo?
You can request a deletion in some clients, but everything (including a like) is like an e-mail here. Once you sent it, people can keep your "e-mail" forever. It's on their inbox, not yours anymore. You can't delete things that are in somebody else's inbox, including your Like. But you can ask them to delete. :)
More like being live on TV. Emails usually only go to one recipient so the damage is limited if you fumble it. Un-deletable nostr has much more potential for public embarrassment. nostr:note1uta8dt0xdt8hezpmh5lvm6nw4uh8qj42x9qtxnp3zd6xesefx2cqtt4nd4