You can also buy long sleeves swim suits, or You can find Dermaflage at most drug stores for around $40.
Dermaflage is flesh-colored, but you can apply makeup on top of it if you want to.
Dermaflage is flexible, so it will move with your skin as you walk around. If it’s a Christian camp you could also say that your get burned easily. Or you could say that your very religious and that you don’t usually wear reviling clothes, this would make sense and I say this a lot, you can wear light white cotton t-shirts under your summer short sleeves, and light blouses over your tops too, it can look very nice if you look it up on Pinterest, and tell your mom that everyone at the camps have long sleeved swimsuits