Hi ihope someone can help me identify this type of growing rash in my left arm it's not itchy the rash was soft but on the lower side is kinda hard.

We really don't have an idea. I woke up this morning then I realize i had this rash I thought it was just an insect bite its kinda big but not alarming. But this time 1 am I realize it widens and it's itchy. Not really sure if this is a ring worm. I hope someone can help what should I do.

The last pic taken at 8 pm