i need help :/

i’m really at a loss! baby started with what looked like a heat rash about 3 weeks ago. i took her to the doctor, they didn’t seem too concerned. said to use aquaphor or vaseline to keep it moisturized, and a small amount of hydrocortisone if she kept scratching.

2nd week goes by, heat rash seems to have cleared, still a bit of dry skin but nothing to be too concerned about. then last wednesday, i’m changing her diaper and notice her skin under her chin is red and splotchy and spreading down her stomach, took her to the doctor same day and he said doesn’t look like hives, could be dry skin but not eczema. again not too concerned.

now today, she’s been scratching at it more, and it’s more red than before and now raised. looks likes it’s up behind her ears too.

any ideas what it could be ? she has no other symptoms, just red raised skin, and it itches - she’s constantly scratching or moving her head side to side, even in her sleep.

i’ve put aquaphor, a&d, breast milk, given her milk baths, i use fragrance free detergent and body soap and lotion.

the pictures are after a milk bath.

i just don’t know what else to try - gonna try and find another pediatrician tomorrow, to get a second opinion.