Persevere with it. I know DD took a good three times with regression before she mastered it. Perhaps my DD wasn't quite ready when I thought she was but I didn't go back to nappies/pullups. I know it is a PITA to constantly wash but stick with it. Just keep reminding her to use the toilet & don;t make a big deal witht he soiled undies. I think I did that a few times & I think that contributed to DD being worse.