I'm just realizing that I didn't read carefully that you weren't at your own house! Deep Woods Off is the only thing that works for me (mosquito magnet) and the chemicals are worth it for that. I love the Deep Woods Off wipes, which you can take with you if you're not sure you will need bug repellant, and then apply it if you need it.
I have tried a lot of the natural options and I will still get bitten. I was once a bridesmaid with a large group of bridesmaids for a wedding, outdoors taking pictures, and I was the only one in the group who got tons of big ugly mosquito bites. They LOVE me
And I haven't found anything to help with the itching and I have tried Zyrtec, topical corticosteroids, menthol, ice, baking soda, heat, fingernails, LOL...