An old farmers tip, which I use all the time (when I'm working in the garden)... Vick's Vapor Rub. I put a dab or two on each temple, my hairline above my far head, on my neck, under my chin, and at the back of my neck. This has been remarkable effective in keeping bugs away from my face... especially when working outside in the evening. A bonus to me is that I love the smell... but not all my loved ones feel the same.
P.S. I've been using the same jar for eons.