Lights out in part of the house
I'm a little confused by "lights out in part" vs. "caused an[d] outage". If you have really had everything go out ("outage"), then this is definitely "call utility" time. If you measure the voltage (when things are working...) and see an imbalance - e.g., 140V on one circuit and 90V on another - then it is definitely "call utility" time.

Do you have a multimeter that you can test voltage? If so test outlets on both sides and see if you get consistent results. If you have a neutral problem it may actually be at meter or outside and is then a utility problem. I suggest calling the utility and telling them you have "intermittent outage and possibly a lost neutral". They should come out quickly to investigate. If the problem is on their side they will normally fix at no charge. If they determine it is on your side then you will need to call an electrician to diagnose a panel problem.

CALL THE UTILITY FIRST!

From what you've described (not 100% clear), it may really be a panel problem. But the problem sounds "big" enough that it could really be a utility issue. If you call the utility and they determine everything is OK up to the panel, there will generally not be any charge (they are concerned because these are potential life-safety issues and will normally send someone to check without any charge).