Where did you go swimming? In a public pool, a friends or your own? I know in public pools sometimes the chlorine levels can be rather strong. So it wouldn't surprise me if you broke out from that. You can try a controlled study by dapping a SMALL section of chlorinated pool water on your body and see if you react to it. If you don't it may be something else that you were allergic to. Were you out in the sun by chance? Get a slight burn? I'm not sure where you are from but here in the states they have an oatmeal bath made by Aveeno that will help take the sting out of a rash and if you are itchy, try Benedryl. Aveeno also makes wonderful creams to use on rashes. I hope this helps a bit and btw, welcome to Healingwell!