my baby is 4 months now and lot of saliva is coming and she is sleeping in reverse position head down way and when can I start solids she is a formula feeding baby

A. hi excesse saliva can be a result of teething or it should be there as baby's digestive system is becoming ready . so as such no need to worry just keep the mouth part clean to prevent rashes you may use Babyhug bib to prevent skin rashes at neck and chest part due to excess saliva.