What Causes Slimy Chest Mucus For A Month, Causing Nausea And Vomiting In My Toddler?

Good day, my daughter is 13 months old and has had a slimy chest now for a month, she gets nauseas because of it and throws up, she s been on two different medications for it but nothing has worked so far, should I be concerned, what can it be and should I go back to a Dr