Hi.. Thanks for the query.. There is a possibility that the any of the salts or other ingredients used for the detox foot bath therapy has caused an allergic reaction causing Contact Dermatitis. Due to reaction there us itching and blisters over the hand and feet.. It does not look probably like a fungal infection, but if you have a doubt consult an Emergency room and get evaluated clinically. For now to reduce itching you can apply a steroid ointment over the bumps, you can also apply Calamine lotion or Benadryl cream for reducing itching.. You can take anti allergics like Levocetrizine, Benadryl, Allegra for relieving the itch and resolving the bumps.. Do cool compresses or ice packs over the itchy areas to reduce inflammation and itching.. Avoid scratching the bumps to avoid infection and further injury to the skin.. Hope this helps.. Regards.