Hi
Welcome to the MedHelp forum!
This could be psoriasis, ectopic dermatitis, contact dermatitis, discoid eczema or any other eczema. Please consult a skin specialist. Take care!
Those look like Hives.... and you only get it after bathing and when your feet are warm? I wonder if you're allergic to something in your shoes and perhaps your soap. Although, it's more likely to be cholingeric urticaria. That's almost like an allergic response to heat - your body responds to increases in temperature by breaking out in hives. (Almost an allergy because of the reponse, but there is no IgE formation, so it's not REALLY an allergy). It can be painful and itchy, but it's typically not dangerous.
Definitely see a doctor and describe what you're describing here. They may do allergy testing to rule out other possibilities, but they should be able to confirm whether it's cholingeric urticaria or not.
Good luck!