expression, godan verb (-ru)
get over a bad mood; brighten up; recover one's temper
Describes someone's mood improving after being upset, sulky, or in a bad temper. Often used when a person's mood naturally recovers or after some conciliatory action.
しばらくしたら、彼の機嫌が直った。
After a while, his mood improved.
お菓子をあげたら、子供の機嫌
When I gave the child some sweets, they cheered up.