I Got A Bite 3 Days Ago On My Foot

I got a bite 3 days ago on my foot it just looked like an ant bite but it's now dark purple. It's not really swollen and doesn't really inch anymore. I don't have any symptoms as those of a brown recluse bite. I'm still worried though because I've never had an infect bite turn this dark purple color. What could this be? Should I be worried??