One of those things bit me on the left foot many years ago and I got sick from it. My foot and leg swelled up to three times its normal size. I still have the scar (I developed cellulitis) and had to have a shot of penicillin to prevent "blood poisoning" as my grandmother used to call it. It was a nasty bite for sure.

Try peppermint oil. Buy it at a health food store and dab some around the house, especially in dark corners where spiders like to make their homes. They hate it---it burns!