Help!!

I need help!!! So for the last week I've been getting really itchy around my neck area but it suddenly stopped when I got my period. My period ended two days ago and actually came two days early after my period I've been spitting on and off. I just took my shirt off to shower and seen this for the first time. It doesn't itch or feels tender. Idk what this is I don't want to be over dramatic and run to the emergency room. Any ideas of what this could possibly be.