What can I use for acne at the back of the neck/head?

Thank you for the enquiry.  Primarily it may be good to consult a Dermatologist, but in the Creme Classique Range, I woould suggest the following:

Zinc Pyrithione Shampoo, the hair can be washed daily, as it is not harsh on the hair and Zinc is very healing.

Cleanser, soapfree wash 2 x pd and rinse off.

Beta Hydroxy Gel, apply a few drops over the area and leave on, it is a toner as well as an ex-foliater and helps improve acnee.

Acne Gel, Apply 2 per day on the area, but take care not to bleach clothing.

The Cream, Dry skin Moisturiser, is a good moisturiser and anti-bacterial which will not block pores and cause further acnee.