^^^ Okay OP just to let you know that I was DCing when I first came into this thread (after a my first ever Henna treatment). Anyway after my Henna I DC'd as usual and then did an ACV rinse (as suggested by Nonie - thanks Nonie). I think I added about 1.5 tablespoons of Aspall (UK brand) ACV to about 1.5 litres of my homemade tea infusion (green tea, white tea and nettle tea) and I must admit that my hair is not drying out as quickly as it usually does (i.e. as per your original posting).
Anyway I will continue to keep an eye on things and hopefully these rinses will help my hair and esp my scalp and keep them both healthy.
HTH's