Hi im not in the beauty industry but i am a self employed hairdresser renting space in a salon with the other girls like wise.
we have recently taken on a saturday girl of 14, who we all pay between us and so she is responsible to us all. although we made her watch shampoos before letting her have a go she still hasn't grasped the concept well
i dont like being nasty and hurting or upsetting people and like yourself wanted to say something with out knocking her confidence because we have had complaints about her washing skills.
I broached the subject by asking her how she was settling in as its been a good month now and basically said now shes had time to settle in which is the hardest bit sometimes, we needed to go over her techniques again and personal skills to perfect them.
i made her watch another shampoo step by step and will wait to see how shes taken it on saturday. obviously your employee is far more capable but all us professionals know you don't become a hairdresser or therapist until you work as one no matter what a piece of paper says.
you could always sit her down for a chat to see hows she's getting on with the products, finding her feet in a new environment etc. and see if she touches on any problems with the products which could translate to her technique and then you could bring up feedback you've received and offer advice.
hope that helps some what?? let us know how it goes x