Nitro patch?
Yes. Like those used by heart patients.
I was caring for my grandmother the first time I used that treatment.
2nd time I used 1/4 nitro pill, a drop of water and a band-aid to hold in place.
I have since used it on other non identified spider bites. Works ever time. May need more than one treatment.
It will even work on old bites. Don’t expect a doctor to prescribe this. Some doctors have used this. I discussed this here on FR a number of years ago. At the time I had the doctor’s name. The original link no longer worked.
Here is the original 2009 post I made the comment on:
https://freerepublic.com/focus/f-chat/2360399/posts