I know what you mean i use to get it terrible when i was a kid every where. yup even on my unit . the thing itched like crazy and swelledto double its size maybe more. scary seeing i was maybe 10 at the time. sometimes i never could figure out how i got it I'd look back and say all i did was ride my bike how could i get it from that. I haven't got it in years thank God . i don't know if you build up an immunity to it or i am just very aware of what it looks like . anyway i feel your pain and hope it doesn't itch to much. Is it possible it is a reaction to something else ? did you say you where welding, maybe flash burn ? sometimes my skin would react to a lot of welding if the skin wasn't covered good while doing it