rash on neck

Or maybe it is just dried blood but it didn’t come off after bathing tonight. Luna is not in pain nor picks or scratches at it. Should we be concerned? I tried the black light to see if it was ringworm but it did not glow. Thx!

She's 4 months old, we just brought her home a little more than 2 weeks ago, she's started having rash 2 days ago, I bought chlorhexidine wipes for her using once/ twice a days,now it turns out brown dry scalp, did I made it worse? we are taking her to vet tomorrow, She's been fine since we have...