What helps get rid of milk rash on baby’s chin and neck

He doesn’t lay flat , I lay him in a boopy to prop his head more than the rest of his body .He just likes to spill a lot of milk out of his mouth while he’s drinking it and he spits up as well . He uses a bib but it’s not enough it still goes through.

@genessysa i don't know because our daughter and son's didn't have that problem. Our daughter spit up a lot but I always held my children during feeding and wiped their faces and necks immediately.