Mom is in early stages of dementia. She keeps yelling help! When I ask her what's wrong she says her butt hurts. Any advice?

Moms been in a nursing home for about a month now. There's still hope that she'll be able to come home.

Recently after a nasty diaper rash has all but cleared up, she's started yelling help! Or oww! When I ask her what's wrong she says her butt hurts I ask her if she needs the nurse or if I can help her. She usually says there's nothing I can do. I get the nurse against mom's wishes and they check her briefs or turn her on her other side or give her a pain pill if it's time. Then, five minutes later regardless of what's been done she yell help! Or oww! Again. I ask again what's wrong and she says nothing and she's sorry. Then she does it again. It's getting worse. Her butt is almost healed but if it's something else no one can find it and she won't say what it is.

I've tried to lighten it up a little by reminding her of the boy who cried wolf and she laughs then a while later yells help.

Has anyone gone through this?