All children go through phases like this.
Do you have a bedtime routine? Worth setting one up if not.
Something like: tea at X o’clock, a little chilled play time, bath, pyjamas on and story in bed. Hot milk.
You need to stay with him for a while whilst he drops off.
Give it a couple of weeks and it will be like it didn’t happen.
Not qualified, just a full time Dad speaking from experience.