Hi. I'm online and happy to answer your question today.
Do you wear contact lenses?
And, no, excessive exposure to the sun -- even the wonderful sun that shines over the Hawaiian islands -- would not cause your symptoms :)
The light sensitivity could mean that you have some inflammation inside your eyeball itself (anterior uveitis) or it could be from anterior segment/exterior disease.
It would be best to be seen by an ophthalmologist just to be sure that nothing significant is going on. But, you could try cold compresses and frequent use of artificial tears (you can get these OTC almost anywhere) and see how things go.
it seems to be really watery again with a bit of a grainy feeling
If you eye continues to get worse, or if your vision is affected then have your eye looked at.
It could also be an allergic reaction, since you are traveling
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