I Notcie a Small Half Circle Bump on the Back of my Neck 5 Days Ago and It's Growing, What Could this Be?

I notcie a small half circle bump on the back of my neck 5 days ago. it didnt itch at all. But now it keeps growing and more bumps are showing up and rite now it is very itchy yester day i put hydrodortisone cream on it to help reduce the sweeling but i dont think that work

No doctor answers yet