sun poisoning? perhaps?

I was at the beach all day yesterday in the water. I was wearing a wetsuit so my face got sunburnt. But on my arms and chest there are tiny red marks. They don't hurt or itch much.. its almost like freckles. I was on antibiotics because of an infection in my gums.. but it was the 6th day i was taking them and i hadnt seen any signs of me being allergic to it or anything ... It seems ridiculous that they would be on my arms and chest, when my arms and chest are protected by a wetsuit. My face doesnt have any. What is this? Will it just go away naturally? ( i think i have had this before, but not as much as this, in the past i think maybe a little bit on one arm..) Do i need to do something to make it go away?