Well my poor little Sophie has go chicken pox (a week before she was due to be vaccinated no less

). She is mostly OK BUT a large amount of the spots are in and around her bottom (front and back).
I am being super careful during nappy changes to be very gentle and I am using muslin clothes and little flannels with water to wipe (rather than baby wipes) but my question is: what can I use to sooth the area? I have Calamine lotion and Weleda Combudoron gel for the rest of her body but I can't use in in and around this area.
PLEASE does any one have any ideas of what I could add to the water to help sooth and calm the area, it looks so sore