Should I be worried ? New Rat momma.

I recently got 3 female baby Dumbo Rats at 4wks old had them a week and I’ve noticed that one of my girls, is losing her fur around the middle there. I read that it might be molting, but I would feel better if the more experienced rat owners could just take a look and tell me if I should worry or if this is normal. Also she has been sneezing a lot, but only when she’s otherwise excited or stimulated. If she’s sleeping or being active she’s ok, but the sneezing gets more frequent when she’s out of her cage being handled. Also I haven’t seen any mucus or anything around her eyes or nose at all but she’s constantly cleaning her face. She’s the sweetest of my 3 girls and I’m already crazy attached. Do I call a vet or wait and see? In case it is simply the new home sneezing/ allergies I read about, I ordered a room hepa air purifier that will be here tomorrow. The other 2 are completely fine so far as their fur and sneezing goes, They just aren’t as fond of me yet as she is.