What Causes Bleeding From Gums In A Child?

My daughter is 16months old and she had her molars coming in but her gums above her front top four teeth are swollen beet red and this has been like that for four days then all of a sudden last night she had blood while she was sleeping coming out of her lips so I checked and it was coming from her top front teeth gums...I have tried lightly brushing them which made them bleed again then they were not bleeding while we slept but when we tried giving her orajel this a.m.they bled again and it s not just pink spotting its a mouth full of blood almost but always stops on its own! What is this or what should I do?