I was on a raft all day saturday and woke up sunday with a few spots on my legs that look kinda like a rash today they are blistering what are they ?

Sun burn, all. rxn.: If you did not use sunscreen while rafting, sun burns can blister and itch if severe enough. Depending on whether you were also camping, there may be a variety of bugs and plants that can cause allergic reactions. I can not further assess your symptoms with only the information you provided. Please contact a doctor if this gets more severe.