Burn blister and swimming
It should be fine. As long as you wash it when you are done swimming. I've swam with popped blisters before and they were fine.
I wouldn't go swimming! :c I think it's a second degree burn..? Since it blistered and those should be taken extra care of. And especially since you accidentally popped it. Even though it's "pool water", the chemicals can cause irritation and/or infection and it may hinder the healing process.
Here is more information :)