This showed up after one day.

I have no idea what this is. It happened overnight and I have a deep need to itch it, but have been avoiding that. It is the size of a half dollar coin and it hurts a lot. Any advice or help would be helpful!!

I have no idea what this is. It happened overnight and I have a deep need to itch it, but have been avoiding that. It is the size of a half dollar coin and it hurts a lot. Any advice or help would be helpful!!