Additional to that, I did a test once and if you’ve ever had a splash of tan on you, you will know that a dot of tan once developed can be an inch wide. So whilst rain washes off bronzer, unless it was a rainstorm and you got soaked it wouldn’t really affect it much at all as tan in the nearby non-rained in areas would spread. So once washed off should be fine however it’s very common to have a couple of white patches on deltoid area from dry skin and anywhere else with dry bits, and those are usually able to be blended with a bit of exfoliation after a couple days so can do the same if needed. Can also use a cotton bud to put gradual tan or tan solution on those bits to match up too.