I got bit by a Brown Recluse about 8 years ago. Got real sick (like a bad flu) for about 2 days before I noticed the bite. I had just talked to a guy a week or so earlier about how to identify and treat a BR bite, should I ever get one. He referred me to the website below.
https://www.badspiderbites.com/spider-bite-treatment/I followed the procedure he outlined and within 2 hours, the symptoms had diminished substantially and were gone before bedtime. The guy was Gerald (first write-up on the website) and he was in our gun club. I was fortunate enough to know a vet who helped me out, too.
Sounds crazy, but it worked for me.