i wouldnt recommend nettle for young children. herbs in general can be too much for children. I cant say for sure, but often times rash in and around the ears are fungal related and histamine related which could be pertaining to food sensitivities from low IgA and high IgG, IgM and IgE in the gut.
chamomile tea could be ok and soothing and slippery elm tea but check with their doctor first. clearing pathogens from the gut and repairing the gut lining is recommended. gelatin can help repair and fungisode antifungal could be beneficial but check with doctor first.