House Breaking relapse for my Shiba inu?

My shiba is about 7 months old now. He was potty trained within three weeks of getting him. We got him around 3 months. He seems to have gone into relapse. We went almost two whole months without any accidents. But the past week, he has peed and pooped in the house about ten times. I don't know what to do? He normally goes to the back door to go, but he's going in bedrooms and the basements. We try to keep the doors closed but with people going in and out its difficult. Should it get better? He is getting neutered in three weeks will that help?