Sore under chin

My four month old daughter is my little pudge pudge! She has a sore spot under her double chin. 😞 she drools a bunch, but I keep it wiped up. So I don’t think it’s from drool sitting there.

I think it’s from her moving her head back and forth and it rubbing on her clothes. Is there something I can put in it to help it heal or something I can do to prevent it from happening??

Thanks for your advice mamas.