Vitamin b1 is awesome. I know this because as a child I was mosquito crack. I got bit all the time and had horrible allergic reactions. I spent days at a time looking like the elephan man because they always got me on my face. My grandma told my dad to try the b1 and we did. I took one a day and didn't get bit anymore. It was like magic.
If you can find vitamin b1 or a complex that has it in there in liquid form (ask your phamacist) then you are set.
Hope this helps
L.
UPDATED: Also the Dollar General cells these citronella bracelets that are awesome and really work. My bf uses them during the summer. The look like the little bungee key cords or sprialed like old telephone cords used to be and they come in neon colors. She puts one on a wrist and one on an ankle and her kids are covered. When she doesn't use them she puts them in a tupperware or ziplock container with an air-tight lid and waits for the next time. She has had the same ones for three years.