Should I go see a doctor?

A few days ago my friend and I were out hiking in the woods. When we came back to the house I found that I had a bite on my arm. (Bug bite I think) At first I thought it was just a bite so I left it alone. But over the past 2 days its changed: when I touch it its much hotter then the rest of my skin, its super bruised, really red, and hard. There is a darker spot near the middle of it and that spot hurts the most.. Is this just a bug bite? Or maybe a spider bite, tic, etc.? Should I see a doctor?