How Can severe Swelling And Pain In The Ankle Be Treated?

i believe i got bit by a brown recluse spider on my left ankle 2 nights ago. my ankle is 3 times the size of right ankle. i t hurts terribly and cannot bear weight on it. i held a flashlight to the dark reddened circular area & the skin is extremely hot. i can see tiny white spot, almost looks like a commedone in center of purplish deep reddish circular area that looks as though there s a pus liquified below topical skin. i squeezed hard to see if i could relieve pressure to reduce swelling. i just bought epsom salts my mom always suggested them. is this dangerous as i have been all (anaphylatic) to red fire ants bites, spider bites, bee stings. i have 3 expired epipens but haven t had any allergic reactions to anything in a bout 30 years.