Don't pressure or scold.
Regression can be due to:
stress
anxiety
changes in the home/family, routines etc.
Or it can be due to urinary infections too. So then you take her to the Doctor to check.
Or, the child sleeps so deeply... that they don't wake up.
ALSO, night time dryness... is not something completely attained, BIOLOGICALLY, until even 7 years old. And that is normal and per Pediatricians. And 'accidents' at night can still happen. That is normal. Kids have accidents.
My daughter is 7.... and ONCE in a blue moon, still wets the bed. Because, she sleeps so deeply.
At certain ages, they then sleep more deeply. Developmentally, too.
I, do not wake my child at night, just to pee.
I rather them sleep and not get lack of sleep.
BUT, I use, water proof bed pads, directly under my kids.
I got them from Amazon.
My daughter, was still wearing night-time diapers, at 5 years old. Pull-ups, are useless at night... because it does not hold much and is expensive. Pull ups are better for daytime.
all the best,
Susan