What is a pronoun for the concert?

You can't use a pronoun to refer to a concert directly. Pronouns replace nouns, and "concert" is a noun.

Here's how you could rephrase your sentence to use a pronoun:

* "I went to the concert last night. It was amazing!" (Here, "it" replaces "the concert.")

* "The concert was sold out, but I managed to get a ticket. It was worth it!" (Again, "it" replaces "the concert.")

If you can provide more context about what you want to say, I can help you find the best way to use a pronoun.