Bad rash on my neck and around neckline

[trev040404]

​Please help me identify these rashes on my skin. The back story on these rashes is this:
Where I work it gets very hot and I frequently am drilling through aluminum so I get metal shavings on my skin. Ive been working there in those conditions for 7 months so an allergic reaction to any of the elements would be highly unlikely. The rashes first began on Thursday it is now Sunday afternoon. The conditions I was working in were maybe 88* and very humid. I was sweating a lot. My initial suspicion was heat rash or eczema. None of the rashes appear to be bumpy. The rash on my neck has a long welt where I believe I scratched it Thursday and the rashes on my arms have inflammed since Thursday due to excessive scratching. The skin irritation doesnt appear to hurt much but is definitely itchy and somewhat sore.

[trev040404]

ive uploaded my profile picture to the picture of my neck currently

[purple1234567]

Not knowing anything else about you- it sounds like it could be a combination of the heat and an irritation from the metal- I don't recall where to get them, but companies make neck wraps that are cooling and you can wear them around you- it might be worth trying something like that in order to keep the area covered and cool to see if that helps.  

[trev040404]

ive been working in these conditions and worse for the past 7 months. Ive never had a rash like this before and it is frusterating for me as well.... it just came out of the clear blue. The spots on the creases of my arms make sense as possibly being a form of eczema since I have hairy arms and while sweating the forearms and bicep region constantly rub on one another. But this rash on my neck came out of nowhere and hasnt subsided. I wish I could post a picture

[trev040404]

it is somewhat blotchy in other areas but mostly just the creases of my arms. It is not head lice. Doesnt appear to be scabies. I have seasonal allergies but never experienced rashes before. Im 30 years old.