I do NOT think what the OP has endured is a spider bite.
I think it's MRSA, because EVERY symptom he describes fits it to a Tee. It's a nasty bug that is expanding like wildfire, and is prolly the most mis-diagnosed condition in medicine tody. MRSA means methicillin resistant staphylococcus aureus, a staph variant that is immune to common antibiotics.
I speak from experience.
I had something that looked like a tiny spider bite, small, red, and looked to have a tiny "head". In 36 hours it progressed into a massive 2-3" infection, like a nasty ingrown hair/boil that was very painful to the touch and HOT. I knew something just wasn't right. I was fortunate one of my close colleagues is a gifted surgeon with the Hands of God. I snuck into his office, and he diagnosed it immediately, took a culture, and proceeded to lance it, having to go very deep to get the root infection, gave me a script for some powerful antibiotics.
The tests came back MRSA. Do a search.
The infection finally subsided. I had a couple of minor issues, like bad zits on my back and upper thighs I didn't relate to the first infection. Then 3 months later, ANOTHER infection popped up, just like the first, HUGE, rapidly expanding and angry. I went an Infectious disease specialist, the Medical Director for my old IV Therapy/HHA company, who took a look and knew what it was immediately. He put me on a regimine he called "decolonization" to get rid of the bug. The antibiotic he described, one of only three that can treat MRSA and the only oral one, was Zyvox...and cost (yes, this is the real cost) US$2200 for a 14 day regimine. The other drugs are IV, and would have been $14,000+ for the same 14 days. The decononization procedure consisted of the Zyvox, daily head-to-toe and all orifice cleansing with Hibiclens, an expensive antibiotic soap used in hospitals, and twice daily deep nasal swabbing of a strong antibiotic ointment...I mean DEEP...
Finally, the infections have been gone for well over 6 months, and no signs of returning.
I have determined I "caught" it at my gym, where handwritten signs popped up one day saying to wipe ALL equipment with an antibiotic solution before use. I talked to the manager, and he admitted they got word of a rash of infections from customers. I don't go there any more.
MRSA has been in the news a LOT lately. It is the #1 problem in health care facilities around the world today, and rapidly spreading. It is often misdiagnosed as a spider bite that won't go away and is not affected by most drugs. It kills in folks who have compromised immune systems, and becomes blood borne. It lives in the mucous membranes of the nose and is spread by contact and airborne. It looks for an opportunity to get beneath the skin, some small opening, where it can do it's thing.
IMO, this is worth the OP considering because it sounds EXACTLY like what I, and MANY others, have gone through.
<edit> The salves, creams and natural therapies will NOT make this go away, period. It is an aggressive bug immune to virtually everything except three antibiotics. The fact it has hung around so long speaks for itself and verifies what it is. Go to an Infectious Disease Specialist NOW, and specifically ask about MRSA.
There are anecdotes about folks who don't have it treated, where it can get into joints and literally disintegrate the bone, with permanent damage.</edit>
