I Went Swimming In My Pool From Walmart Two Days

I went swimming in my pool from walmart two days ago, I only wore a shirt no bathing suit and swam like that. Then a couple hours later when I showered I felt a burning pain inside my nipples, almost as if the skin had rubbed off and the water falling onto them would only worsen the pain. Then today I showered and felt the same pain, only this time it seems although there are bloody bumps on my nipples??