“Sorry, just needed to get some shit done before I could party,” I reply, “how’s the party going?”
I see what the author is trying to do here, but this is punctuated incorrectly. When you have a complete sentence in your dialogue, you still need to use a period somewhere. Then you can restart your dialogue with a new quotation mark. You can use two commas here when you have a continued sentence with a interruption for a verb of speaking.
Should look like this instead: “Sorry, just needed to get some shit done before I could party,” I replied. “How’s the party going?” (These are two complete sentences with a change in topic, thus should be separated by a period)
