everyone has a bad day...

figured the entire body of work would be your review especially if you seen her a bunch of times. If the next couple of times is not up to par you could say she was good for a couple of years and then her quality dropped off.  

A lot of guys are one and done...but I feel if you see the same girl for a long time you should explain the body of work if possible and not just one encounter.

to express your concern to her - but perhaps she was too out of it for this?
If things were really that bad, I think I would have expressed my concern, then left early, saying I'd meet again another time when she was better.  I think you should write her a short note of your concern, even if for no other reason than to help her realize that whatever she has going on, it really affected her performance, and thus will likely have an impact on her business if it continues.

He's not asking if he should give a bad review or stop seeing here he's asking if sending a note would be ok. Seems reasonable to me though always a risk it offends her. Maybe she has the bad cold that's going around and thought she could work if she took a lot if meds.

There is only one provider in your review history that fits the profile. Even if it is not her, people will start to speculate which is not fair to her.