Dd went through something similar just before she started to use the potty consistently. My uneducated guess is that she was upset about getting her diaper dirty because she wanted to go in to the potty, she was just still unsure about it. We had the same denials "I'm not poopy" = she would even blame the dog! 
We talked about diaper rash, although it has been quite a while since she has had any sort of rash, she remembered it. We would say "if you sit in pee pee and pooh pooh you will get a rash" in the same mattter of fact way that we say "if you dont wear your coat you will get cold outside" - just a very fact of the matter sort of statement. This lessened the fight to change. Also, we did the standing diaper changes and even plopped dd in the shower to wash off (toddler poop is m-e-s-s-y!)
Plus, we had to stop using her "baby diapers" - I think I loved them more than she did
(beautiful daisy doodles). Dd goes to daycare and she saw that the other preschoolers were wearing pull ups. I tried to get her to wear cloth ones with no luck. Shes quick 
We still let dd choose what she will wear. Sometimes its underwear, sometimes a diaper. She even wore underwear to school twice last week and stayed dry, then this week she decided she wanted diapers again. The important thing to me is that she decides what she is ready for.
It will end
but I know in the meantime you feel 

We talked about diaper rash, although it has been quite a while since she has had any sort of rash, she remembered it. We would say "if you sit in pee pee and pooh pooh you will get a rash" in the same mattter of fact way that we say "if you dont wear your coat you will get cold outside" - just a very fact of the matter sort of statement. This lessened the fight to change. Also, we did the standing diaper changes and even plopped dd in the shower to wash off (toddler poop is m-e-s-s-y!)
Plus, we had to stop using her "baby diapers" - I think I loved them more than she did
(beautiful daisy doodles). Dd goes to daycare and she saw that the other preschoolers were wearing pull ups. I tried to get her to wear cloth ones with no luck. Shes quick 
We still let dd choose what she will wear. Sometimes its underwear, sometimes a diaper. She even wore underwear to school twice last week and stayed dry, then this week she decided she wanted diapers again. The important thing to me is that she decides what she is ready for.
It will end
but I know in the meantime you feel 






. This seems OT to me.
There are many of us who disagree with your authoritarian view of controlling children. Welcome to MDC.
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