A strange rash/red lump appeared on my leg a few days ago and now there are around 30 of them on my two legs and a few on my arms. I have taken pictures of them. Can I send a picture? They are a little itchy when they appear but then stop being itchy very quickly. I'm not sure where they came from, but recently it's summer and I have been in the grass a fair amount and once went swimming in a lake.