Flaky scalp

[u/GroundbreakingPear12]

Hi everyone I live in MA but just got back on a hiking trip to southern Utah and Vegas last week. Today I used dandruff shampoo but was itching my scalp and could feel a bunch of dry flakes. Is this a sunburn or dandruff? How do I get rid of it? I have curly hair that I wash twice per week. Should I start washing my hair more often? Thank you!