Anyone know what this could be?

I have had this in the crease of my arm for over 3 weeks now. It doesn’t spread or anything just flares up really bad and becomes itchy and painful. The story is, I had blood taken here and about 3 days later it showed up with a patch then turned into several dots around it. I have tried anti itch cream, desitin, Coconut oil everything and all this does it dry up then flares up again in the next day or so. It’s not poison ivy or anything like that as I have not been outside to get it. Looks a little better in this picture but when it flares it looks horrible.