Sorry about the length.
Yesterday, after hiking up a mountain, I stopped for a short rest on a rock near the trail. After a little while, I felt a sharp sting/bite on my ankle from what I thought might be a bee (not quite like a wasp sting, more like a bumblebee). However when I looked down to brush it away, whatever stung me was gone, so I have no idea what it was. The pain quickly subsided and I was left with a little bump that looked like a mosquito bite, but it was not very itchy. I thought it was odd that a mosquito bite would be that painful, but wrote it off. A few minutes later I felt another sting/bite on the other ankle, but again did not see whatever it was that stung me. It didn't concern me too much though, and I continued my trek down the mountain.
Today, when I woke up, the bites areas each had purple bruises around them about an inch in diameter. My ankles were quite swollen around the bites and very painful - not itchy, however. My ankles felt a little stiff so I tried to rotate them a few times. Now, they are still stiff and it's painful to extend/point my foot out and in. The bruises are darker than before and irregularly shaped - roundish with tiny little spidery lines about 2 mm long coming from the edges.
When I searched the web, I kept getting results for poisonous spider bites and everyone suggested emergency care immediately. However, as far as I know, we have no poisonous spiders anywhere near my area and I've never heard of any case of blood poisoning from a bug bite.
I've been icing and taking ibuprofen for the swelling but have no idea what bit me or what my body is doing about it. Could it be an allergic reaction to a specific bug? Or do I need to report a poisonous spider sighting in my area? Is this serious?
I can post pictures after if needed.