What is this bug bite from?

I woke up with this bite on my right leg a few days ago. It hurts and itches when I walk and it’s gotten bigger ever since I noticed it. The area around the bite (not sure if you can see it) has gotten redder and the pain hurts more and more.
It’s driving me insane. I slept on the floor last night because of it!
Does anyone have a clue on what it could be?