My client is developing red blemishes using the HSR products.

If a client shows allergic reactions, it is probably due to the night serum.  
I would then temporarily avoid using this serum and try again after a while.  
It is important that the client does not use anything else during the treatment period.

(Why the night serum? Because this is the only one of the two lotions that contains an essential oil and as is generally known, essential oils are fairly sensitive to provoking allergic reactions).

Another possibility could be that the customer is using a shampoo with SLS (sodium lauryl ether sulphate) or ALS (ammonium lauryl sulphate). These substances can precipitate on the scalp in very hard water and cause flaking and redness, as well as eczema-like spots on the skin.