What's this red itchy rash with small white bumps? Going on day three.

[ChristianaKey]

It's been really hot in NYC and I had a few sweat pimples pop up on my neck. I put some tea tree oil (undiluted and kind of old, which I've now read was a terrible idea) on top of them to clear them up. I slept on my boyfriend's arm the next night (no a/c in the room) and the area was red. I put hydrocortisone cream on it, but that may have spread the tea tree oil, because by the afternoon, the whole area was read and there were about 20+ more little bumps. I cleansed with witch hazel on a cotton ball, which helped the itching slightly, and put an ice cube on it, but the itching and redness keeps coming back (I have only accidentally itched the area once). I put a topical prescription-strength steroid cream for my psoriasis on it, and the redness has gone down slightly, and it's just a dull itch, not a fiery itch like before. I need advice on what to do! I work in the food service industry and I don't want to look gross for customers!

[ChristianaKey]

Here's a photo: http://www.medhelp.org/user_photos/show/762914?personal_page_id=5891086

[NYLIFER]

I hope it vanishes quick. I am also in NYC in this swamp heat w no AC.