You poor thing, I had no idea spider bites were so bad
I’ve not had a spider bite. But, fire ants when they bite me are super bad. If I do anything to the blister which forms over the bite, the skin quickly ulcerates and it becomes terribly infected. I cannot imagine a reaction from spiders.
One thing I’ve learned overseas, for such a skin reaction or a deep skin wound, slather on honey or sugar crystals. Pack that wound as full of the sugar as will stay on it. Mound it over the top and then cover with a bandage. I do not know why, but it speeds healing.