Hi there!
One thing you need to ensure you tell her is that she may suffer lifting of her natural nail bed.
I have Herpes Simplex 1 (the cold sore one) and I have only ever had one cold sore in my life when I got my lips tattooed. The only other time I have issues is when I put on a new set of nails. I took them off just after Christmas and put them on again last week - both my ring finger nails have lifted almost all the way back to the lunula so I have shortened them almost to my finger tips to reduce the risk of knocking them.
The first time seems to inflict enough disturbance to the nail bed that some of them will break out with the herpes. What this means to your client is that she will have to start them off a bit shorter and grow them longer, and that she will have to keep her nails clean and dry. I use a toothpick and just slide it under the lifted nail bed to absorb any moisture, then throw it away. Then get her to use hand sanitising gel to ensure there is no bacteria trapped under the nail, because this will absolutely cause an infection.
The herpes usually resolves itself by the time of the first or second infill.
I use NSI's Nail Pure, after I've washed and dried my hands, I pop a drop of the nailpure down between the lifted nail and the nail bed. It stings, but it does the job of keeping the area sanitized and dry.
Remember that treating Herpes of the nails is the OPPOSITE of a fungal infection - if it were fungii, you'd clip away the lifted nail to treat the fungus and allow it to dry out. Herpes need to be clean and dry, but removing the lifted nail will cause MORE trauma and exacerbate the herpes.
I was in the industry 13 years before I learned that this was the problem.
It is correct that herpes can only be transmitted by the open sores, but these sores can be anything from damaged nail beds, cold sores, mouth ulcers, a sore throat (tiny ulcers popping in the throat) and skin lesions similar to excema. 90% of the adult popluation has Herpes, either 1 or 2, and only 30% of these people know they have it.
Best practise is to assume that everyone has something infectious and they don't know it.
It might seem overkill to wash and sanitize your hands, then donn gloves, faskmask and goggles; but you'll thank yourself later. I use disposable dental mats on my manicure table; I also purchase files for each of my customers, as well as a bottle of sterilizing spray. I send these home with the client in a zip-loc bag, and ensure that all of their files are sterile before use. Hugely reduces cross-contamination. Although this does increase your costs, I provide a hand and arm massage at the end of the service, and I also tell my clients that their nail enhancement includes a manicure (cos by the time you're done, it has!)
I wish you all the best in your venture as a nail tech.