You can get a pretty long-lasting local reaction to a bite, spider or otherwise. You may indeed have had some systemic symptoms at the time, as you suggest, but they don't sound severe enough to be from a black widow.
Since the skin hasn't developed an ulcer or necrosis (skin death), I assume that the changes you still see and feel will probably go away or at least fade over time.
As to which spider, without the spider itself, I think it would be hard. It doesn't matter very much at this point.
You may want to check out the following website http://medent.usyd.edu.au/index.htm
for more information about spides and other beasties.
Take care.
Dr. Rockoff
Hi, june 24 2002 ,I live in upstate new york 100 miles from new york city.
I was bitten bye a spider( im 100% sure) cause it happened in my sleep, well I woke up after I got out of the shower i noticed a red pimple(looking) the size of an eraser on a pencil so i left it . next morning i wake up and have pain blister size of a quarter and red around it, well as the days passed as i found out had ulcers for about almost 2 weeks as the bite was with the redness as big as a soft ball , well went to the doctor he told me put antibiotic ointment on it , well im not sure from the ocean and my pool the 50 cents size ulcer closed up ( well by then it was just a sore) well 1 month later the scar is there with this rash around it the size of a paper plate keeps geting bigger and itchy, along with pain in the area so go back to the doctors i was put on some antibiotics for 7 days 4 times a day. well took them started to almost clear up and bang its back again bigger all over my upper back spreading like crazy. what do i do ( i do have doctors appointment but i think this is gonna be a crazy thing to heal) and , i need some medical advice , cause the doctor i see is new. the scar area is a dark red like purple looking well not that red . and the rash is a raised red area.
help
Amanda