Try- Up your dose of lactulose or the frequency of taking it. My first dose I took 45ml then I took 10ml every evening till I passed poo & then the following days after. Speak to your GP if that doesn’t work or you’d like to clarify. Or speak to your midwife. Im now 11 days pp and it’s only just come to some sort of rhythm. Your bum being sore may just be your tears x
Your GP might be able to give yoi a stronger laxitive/ stool softner to help get things moving along. So always worth speaking to them if you are worried!