My mom is in a nursing home with dementia and paranoia. Last night she punched one of the workers.

Yes, happens frequently in dementia. My mom was hitting and kicking residents, staff, walls. This then required a psychiatric evaluation where they figured out what meds she needed and how much. She had been on ativan, and it had the completely opposite effect on her as intended. Med reactions are different depending on the person. So, an in patient psych evaluation is often the best way to go.

Why were they washing her hair if she had just had it set? Wasn't it washed with the set? Sounds like there may be a communication breakdown at the facility somewhere. Was it set at the facility or somewhere else?

My mom gets really agitated when we try to do anything she doesn't want us to do, but she is now on meds and it helps. So if you think this was a one-time, one instance occurrence, then I'd just wait and see. But if this becomes an ongoing thing, then I'd ask the doctor for a little something.

I might punch someone out if I'd just had my hair styled and someone wanted to wash out the set!

Does mom have a regular bath night? Is there some was you can make sure that she doesnt have someone attempting to wash her hair after she's been to the hairdresser?

Ask the director of nursing to get a prescription for anti-anxiety medication one hour before bathing. Sometimes all they need is a small dose of Ativan and they are not so upset.

Unfortunately it is normal behavior from someone whose brain is diseased. Some people with dementia become very violent. They will hit, punch, bite, strike, throw things at, kick, and spit on people caring for them. It was probably just coincidence with the hair washing. What medications is she on? Is your mom a big woman? Did she injure the worker?