Is this caused by sunburn?

All of a sudden my hair has all this crazy shit dandruff. Its driving me nuts since I have to wash my hair every single day… which is bad for it. I have in braided hair extensions. I just came back from Spain where I went for a 4 day holiday. One day I was the whole day at the beach and never used any sunscreen.
Now I have SO MUCH dandruff in my hair that its very difficult to sleep due to me scratching constantly.
My dad thinks that its maybe because of sunburn but I don’t believe him because there is no such thing as ” hair sunscreen”

whats happening to me?