Will my hair grow back and how will do treat my scalp?

ok i have eczema but i never had any problem with my scalp being dry or flaky untill a few month ago when summer started.ever since ive been out in the sun i notice my becomeing very dry and itchy and i know im not supose to scratch but ive been scraching alot an i went to get a haircut and i notice the parts on my head where dry and itchy there hair missing it like a bold spot but theres still a little bit of hair.i was wondering maybe my scalp is dry because of the sun ?and will my hair grow back?and how should i treat my dry scalp?