I was sued and the lawsuit was dismissed without prejudice. What to expect next?

Dismissed without prejudice means they can refile it again. You should try to negotiate with them to settle before they file again. Or take your chances and see if they ever refile. It is quite possible the case was dismissed because they didn't have all of the evidence they needed to prove the case

Do you know the reason the plaintiff voluntarily dismissed the case? If they realized they had no legitimate claim, then perhaps this is the end of it. Otherwise, all you may be able to do it to wait and see. Have you talked to a lawyer about their claim against you? It may or may not be valid.