Blue spot appeared on breast two weeks after rash

[Sophtee]

Hi!
So I have had this rash type thing on the top half of my body for almost two weeks (red spots, not always itchy, helped when I used antihistamines but haven't gone away). The spots are on my chest, neck, part of my back, and also on  my breasts. I have ruled out heat rash and am not on any medications/am not pregnant and have not recently been sick. Went to the doctors and she has prescribed Hydrozole, and I also got a blood test (waiting for results), however she (and a chemist) weren't able to give me any ideas as to the cause.
Tonight while putting it on I noticed a blue spot on the underside of my breast surrounded by a particularly agitated area (raised, red skin, super itchy), I don't remember bumping my breast in that place so I don't think it's a bruise? But maybe I scratched so hard I bruised it? It's not painful, my breasts aren't painful, just itchy. I know what my breasts look like and this must be very recent. I consulted doctor google and IBC came up (very rare, I know, so I'm not super panicked) I feel fine otherwise, but do you think I should wait to get the results of my blood test or should I go to see the doctor earlier than that?

[mhv]

you could call your doctor, and let them know you found a new area of concern, and see what they say.  what was the bloodtest for, do you know?