Read the following paragraph and answer the question. Give ONLY the answer, no other words or explanation.

For example:

Answer: <most likely answer, as short as possible>.

Paragraph: It was the Reebok 10 K marathon . I was 6 hours standing up , going from one place to the other , collecting tea / coffee cups , napkins , glasses , garbage , serving drinks . My feet are alright , though they hurt . My face ... oh god MY FACE !

Question: What may be the reason why their face hurts ?
They have a sunburn .
Sun exposure or dehydration.