The reason obviously seems to be due to Photodermatitis or sun burn.
You should use an effective sunscreen every 2 hours on the exposed parts of your body regularly irrespective of the weather conditions.
Also, you can use ice cubes on the parts that are prickly and itchy.
Use a good moisturizer all over the body in the nights.
lotion initially for some time for the itching to subside.
Wish you speedy recovery.