suse, i am not sure about the whole BF absorption but there is a good natural produce for kids that may be suitable for you. it is called Scatterbugs made by Cherub Rubs that you can buy online or in good organic shops. it is aloe vera based with lemon eucalyptus.
i am not sure why a petro chemical based one would be less harmful/absorptive as this. but perhaps it does come down to the smell.
GL fighting off those blighters. you don't want to get Dengue, Ross River or other mosquito borne diseases either. my sis who is BFing had RR this year and it was nasty.