Could be a rash from milk going into they’re neck
My baby always gets these maybe a little bit of sweat/heat inbetween he’s neck and chin x
Looks like dribble rash , keep it dry xx
Yeah looks like drool rash to me too. My son was a crazy drooler was always wiping him dry he would get them too especially around his mouth
Looks like it’s a rash from being wet from drool/sweat and maybe milk as milk runs down their neck a lot at that age xx
Heat rash
Heat / dribble rash, please see your doctor and have something for it. My daughter is 8months she had this n initially i applied breastmilk / zerobase lotion etc , thinking it would get better, it hot worst and now my baby cannot sleep whole night due to itching and crying and restless. although its nothing that can harm them but make them restless. i'm going through this thats y explaining you. 🫥
It might be teething x