This an allergic reaction to the Pool Chemicals. Chlorene, And some others. Just take a shower and powder yourself with cornstarch Powder. If it gets worse, some OTC cortisone should suffice!
It looks like an allergic reaction to the chemicals used in swimming pool water especially chlorine. You can take some OTC oral antihistamine medications like Benadryl or Claritin and see if it helps.
For mild-moderate symptoms a weak steroid may be used (e.g. hydrocortisone as dermacort), whilst more severe cases require a higher-potency steroid (e.g. clobetasol propionate, fluocinonide).But they are available under prescription and should be taken only after consulting a dermatologist. Also wear cotton clothes.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.