I am sorry to learn of the rash. It is not clear what products you are using in the range.
The routine to start with would be the following:
Cleanser, soapfree used 2 x per day and rinsed off well
Beta Hydroxy Gel, apply a few drops at night and leave on, this is the toner and ex-foliater.
Either the Safari SPF40 Sunscreen OR the Moisturiser with SPF 30. Both are also day and night moisturisers as well as providing sun protection.
The one, of the 3 products above, that may cause a slight sensitivity, could be the Beta Hydroxy Gel.
If you have obtained more products, the other one that may cause a rash is the Day/Night Alpha Moisturiser plus+.
Stop using the 2 steps and apply the neutral Facial Moisturiser for a few days. It will help if you inform us exactly what steps you are applying.