Hello and Welcome to ‘Ask A Doctor’ service.
I have reviewed your query and here is my advice.
In my opinion your symptoms might be related to
cellulitis, which is common after spider bites. If you have seen any bite entry it might have been a spider bite. In DVT, patients along with swollen feet commonly have strong pain on the affected area, so in my opinion this is not the case. You can try taking anti inflammatory drug,
Ibuprofen two times daily for 5-10 days, and take antibiotics Cefalexine twice daily for 6 days.
However, you should go to the ER for a physical examination and other blood tests, to put the right diagnosis because both are important health problems and you have serious complications if not treated properly.
Hope I have answered your query.
Let me know if I can assist you further.